When Is It Safe To Plant Out Vegetables?

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20180522A marksvegplot.blogspot.ca

There is often a long period in the spring when it’s be warm enough to acclimatize vegetable plants tou outdoor conditions during the day, but still too cold at night to plant them out permanently. Source: marksvegplot.blogspot.ca

Gardeners go through the same questioning every spring: when can they sow or plant out vegetables? Of course, most plants won’t tolerate frost, so do check with a weather service about whether one is expected over the weeks just after you plan to start. However, when there appears to be no risk of frost, is that enough? Sometimes nights are still cold, but days are warm. Is that alright?

Here’s a guide.

Direct Sowing

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Source: worldartsme.com

Sowing seeds is a bit less stressful on the gardener than planting out vegetables started indoors. In most cases, cooler soil temperatures that actually required will simply slow germination down, not stop it. Plus it will take a week or so before the seedlings are tall enough to really be exposed to cold night air, giving you a bit of leeway. When the seeds do germinate, sign the soil is warm enough, usually nights have warmed up too and they’ll simply grow normally. So if you sow seeds a bit early, that doesn’t necessarily delay the harvest to come.

Still, it’s wise to know that some vegetables (cool season crops) germinate quite readily at fairly low temperatures (beets, carrots, lettuce, onions, parsley, parsnips, radishes, etc.) and you can consider it safe to sow them when the soil temperature has reached about 45˚ F (7˚ C), while 55˚ F (12˚ C) is safer for turnips, the various cabbages (broccoli, kale, cauliflower, etc.), Swiss chard and corn. Wait until they reach a balmy 70˚ F (21˚ C) before you sow warm season vegetables like beans, cucumbers, squash and melons.

You can find an inexpensive soil temperature thermometer at a garden center or online. Take the temperature at about a depth of 4 inches (10 cm).

Does the Moon Have an Influence on Frost?

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The last frost date has no relation to the phases of the moon. Source: Myriams-Fotos, pixabay.com & http://www.stickpng.com, montage: laidbackgardener.com

In short, no. None whatsoever. Look it up on any serious gardening site and you’ll see. That it is safe to plant out after the full moon of May (or March, or April, or whatever the local legend says) is just another gardening myth. Like the one that says it is safe to plant out once oak leaves reach the size of mouse ears. Oaks do get frosted occasionally, even when they are leafing out or even in full leaf. You just can’t trust Mother Nature when it comes to frost!

Planting Out

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You don’t want to risk planting seedlings out too early. Source: WorldVegetableCenter

This is where things become serious. You carefully sowed the seeds of many vegetables indoors to get a head start on the season and you’ve been caring for them for weeks. Or you bought them at great expense. You certainly don’t want to risk harming them or even slowing down their progress when you plant them out.

Since sprouted vegetables are immediately exposed to air temperatures as well as soil ones, you’ll need to take air temperatures into account. And by mid-spring, the soil, having absorbed the sun’s heat all day, is often warmer than the night air. Look most carefully at night air temperatures, cooler than day ones … often considerably so! And even when night temperatures warm up, you still have to consider the possibility of late frosts (see above).

Note that you need to acclimatize seedlings started indoors to outdoor conditions before you plant them out (a few days in the shade, then a few in partial shade before exposing them to sun) and you can usually start to do up to 10 days before you actually expect to plant them out, putting them out on balmy days. But do bring them in at night if night temperatures drop to any degree (as they often do early in the season).

There are a few cool season vegetables that are often started indoors, like leeks, lettuce, onions and again, the various cabbages. You can plant them out quite early, when night temperatures remain above 45˚ F (7˚ C)… assuming that, by there, there is no danger of frost in your area!

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Wait until nights warm up before planting out warm season vegetables like tomatoes. Source: www.veggiegardener.com

Warm season vegetables don’t usually die under cool night temperatures (unless there is frost), but instead go into shock and slow down, which delays the harvest. Plant out a tomato or cucumber plant too early and it will actually come into fruit later than one transplanted a week or two later, when temperatures are warmer.

Consider night temperatures of 55˚ F (12˚ C) as an absolute minimum for transplanting tomatoes (but even so, they prefer warmer temps). The other warm season vegetables are even less happy with cool nights. I suggest 65˚ F (18˚ C) for cucumbers and peppers and 70˚ F (21˚ C) for eggplants (aubergines), melons, okra and squash (including pumpkins and zucchinis).


I hope the above information will help you decided what to plant out when!20180522A marksvegplot.blogspot.ca

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Less Fertilizer Less Often for a Beautiful Lawn

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Seek and ye shall find! Yes, 1-step lawn fertilizers do exist! Source: dir.indiamart.com, montage: laidbackgardener.blog

You really don’t need to apply as much lawn fertilizer as most fertilizer salespeople tell you, nor as frequently. The usual 3- or 4-step programs are costly and require a lot of effort on your part. Plus grasses can’t absorb the massive doses of rapid-release fertilizer applied and much of it ends up polluting waterways. Instead, consider the idea that single application of slow-release fertilizer, preferably organic, in the spring or fall, can give the lawn all the minerals it needs for healthy, season-long growth.

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Recycle grass clippings by leaving them on the lawn. Source: www.burbankca.gov

And if you leave grass clippings on the lawn after you mow rather than raking them up, an age-old technique with a new name, grasscycling, that also fertilizes the lawn. The clippings simply decompose where they lie, returning their minerals to the soil where they “feed” the lawn. So, you’ve already given the turf at least half of the minerals it needs. That way, when you do apply your “1-Step Fertilizer,” you can cut the application rate by half, leaving even more cash in your pocket!

Note too that, since these slow-release fertilizers are liberated slowly, grasses absorb the minerals as they are released, so there is no risk of polluting the water table and streams with excess fertilizer.

Less fertilizer, fewer applications and a healthy, green, environmentally friendly lawn? What’s stopping you?

The 15 Pace Rule

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The truth is that many garden infestations really aren’t worth treating. Source: www2.scouts.ca, thenounproject.com & worldartsme, montage: laidbackgardener.blog

Yes, perfection does exist … in some works of art, but not in the garden. There is almost always something not quite right about any plant you grow: insect holes in a leaf, powdery mildew on lower leaves, a brown spot here and there, etc.

While many gardeners immediately reach for the most powerful pesticide they can find at the first sight of a problem, they’re usually wasting their time. Often the insect that drilled the holes is already moved on and mildew is usually the final stage of a disease that started weeks before and has already stopped spreading, so why bother? Plus often, Mother Nature has already sent in her clean-up team in the form of beneficial insects and do you really want to thwart her plans?

When the disease or insect or “problem” is minor or out-and-out inconsequential in the long run, no treatment is really necessary. At any rate, a few pierced, chewed, spotted, or swollen leaves don’t really disfigure the garden, at least not if you squint a little.

That’s why I suggest you apply the “15 pace rule.” It couldn’t be simpler! Before treating, step back 15 paces: if you can’t see the problem at 15 paces, it’s probably not worth treating! And yes, long-time readers, I’ve said this before, but it’s worth repeating!

Among the problems that are trivial and rarely worth reacting to are leaf miners, late season powdery mildew, leaf and stem galls, and yellowing lower leaves.

 

The Long and Short (Days) of Onions

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Day length determines whether onions form a bulb, so you need to plant the right kind, depending on where you garden. Source: clipartix.com & http://www.abc-color.com, montage: laidbackgardener.blog

When you plant onions (Allium cepa), you expect them to provide you with nice fat bulbs at the end of the season. And as long as you buy your seeds, onion sets or plants locally, that’s just what they’ll do. But did you know that onions only produce a bulb worthy of that name when they receive the right day length? In fact, if you grow the wrong kind of onion, there’ll be no bulb at all!

Here’s an explanation.

Three Categories

There are actually three categories of onions: long-day onions, short-day onions and day-neutral onions.

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The 35th parallel north (red) and south (green) help determine where you can grow different types of onion. Source: imgur.com

In the Northern Hemisphere, long-day onions are grown in the North, above the 35th parallel. That means throughout Canada and the northern states of the USA and through most of Europe and Northern Asia as well. They need 14 to 16 hours of sunlight per day, otherwise no bulb is formed. They are usually planted early in the spring for harvest in late summer. Seed companies from northern areas usually only offer long-day varieties.

In the Southern Hemisphere, long-day onions are rarely grown at all, except in New Zealand, Chile and Argentina, as otherwise southern land masses really don’t really extend far into areas with long summer days.

Long-day onions tend to have a strong taste and store well.

Short-day onions are grown between the 35th parallel and the equator, since they don’t produce bulbs under long days. They form bulbs when the days reach from 10 to 12 hours. Given the hot summers nearer the equator (and onions like things on the cool side), they are usually sown in the fall for a spring crop, quite doable in areas with a mild climate.

Short-day onions tend to have a milder taste than long-day onions, but don’t store as well.

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The formation of a bulb shows this onion was grown at the right day length. Source: gardenerd.com

Day-neutral onions produce bulbs under the effect of 12- to 14-hour days. They are planted in the spring in cooler climates for harvest in late summer and in the fall in the hotter ones for a spring harvest. They usually give their best performance on either side of the 35th parallel, so are popular in the south of Europe and in the southern United States (except Florida, where short-day onions reign) and are also widely grown in Australia and South Africa.

Day-neutral onions tend to be intermediate in taste and shelf life compared to long- and short-day onions.

If you grow an onion in the wrong area and no bulb forms, all is not lost: you can still use it as a green onion.

How Pertinent Is This Information?

As long as you grow onions from locally produced seeds, plants or sets, the information above will not likely change the way you garden. But if you order seeds by mail, it is important to consider where they came from. The best catalogs will mention the category their various onion varieties belong to.20180519A ENG clipartix.com & www.abc-color.com

The Perfect Insect Barrier!

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Floating row cover keeps insects out. Source: rhinowindows.info

One of the most unusual yet effective “pesticides” is floating row cover, also called row cover, garden cover or frost cover. It’s a translucent, extremely lightweight fabric that lets rainwater, air and sunlight through to the plants it covers. It was originally designed to provide frost protection for early plantings and can still be used for that purpose. However, I’ll bet dollars to donuts that more gardeners today use it to protect their crops against insect pests. And here’s how it works.

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These very frustrated potato beetles can smell and see their host plant, but the row cover keeps them away. Source: www.amazon.com.

Loosely cover the row or bed of the susceptible plant with floating row cover (install it on a windless day if possible) and use stakes, bricks or stones to pin it down, otherwise it will quickly blow away. Cover the bottom edge of the fabric with soil all the way around: you don’t want to leave any gaps where insects could enter!

When the plants emerge from the soil beneath the barrier, its usual pest will quickly find them by the smell they give off and will land on the row cover, ready to feed. But it can’t penetrate the barrier! You’ll see the poor bug pacing, turning in circles, examining every fold in the fabric, but there’s nothing it can do. Hungry, it will either fly away to some other garden or simply die, unable to feed itself.

If It Flies or Hops, It Will Be Excluded

A floating cover is very useful against pretty much any flying or jumping insect, including:

  • Aphids;
  • Bean beetles;
  • Beetles;
  • Borers;
  • Cabbage butterflies;
  • Cabbage loopers;
  • Cabbage maggots;
  • Carrot flies;
  • Caterpillars;
  • Corn borers;
  • Cucumber beetles;
  • Cutworms (migratory species);
  • Flea beetles;
  • Grasshoppers;
  • Leafhoppers;
  • Leaf miners;
  • Leek moths;
  • Onion maggots;
  • Potato bugs;
  • Thrips.

A properly installed row cover will even keep slugs and snails away—assuming they weren’t relay present in the soil where the cover was installed—and will keep birds off freshly sown seeds. It will not, however, be of much use in protecting plants from soil-borne, non-selective insects that are found throughout in the garden (wireworms, non-migratory cutworms, etc.), nor against mammals like deer and groundhogs: the latter will just chew holes right through the fabric to get at whatever tasty morsel is underneath.

No Support Necessary

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Here hoops were used to raise the floating row cover off the plants, but that is just a waste of time. The cover is designed to rise with the plants and cause them no harm. Source: www.gardening-guy.com

One precision: unlike a cloche tunnel that needs a structure of some sort (hoops, stakes, etc.) to hold it above the plants it covers, floating row cover is so light it is simply lifted upwards by the plants as they grow, so there is no need for a support structure. That’s why it’s said to be “floating.”

That said, a lot of overly zealous gardeners do put in a support structure of some sort, as if they find floating row covers too easy and prefer to complicate things. That’s fine if you don’t mind the extra work, but it’s something a laidback gardener would avoid.

For Early Season Use Only

The only true downside to floating row cover is that you can really only use it early in the season. In most cases, it has to come off by midsummer. And there are two reasons for that.

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You’ll need to remove the row cover when your vegetables start to bloom. Source: rurification.blogspot.ca

The first is that row cover excludes all insects, even pollinating ones. For vegetables that require pollination, such as squash, cucumbers, peppers, beans and other fruit-bearing ones, you’ll need to remove the cover when the first flowers start to bloom to let the “good guys” in.

The second is that row cover reduces air circulation and that does keep the plants a bit warmer than the surrounding air. That’s rarely a problem early in the season and in fact, is often a blessing when cool nights hit after the garden has been seeded or planted. However, during the heat of summer, in many climates, it just becomes too hot under any kind of fabric, even a light, airy one. When ambient temperatures reach 85˚ F (30˚ C), it will be even hotter under the row cover and it’s probably time to consider removing it.

Of course, when the row cover is removed, your plants are then exposed again to their insect pest again, but usually by this time, the first generation of the pest has likely already come and gone. You’ll only be dealing with the second generation (if there is one) and it tends naturally to be much smaller and less harmful than the first one. Better yet, since you deprived the pest of its main source of food at the beginning of the season, the second generation will likely be less numerous than it normally would have been, with usually only scattered pests reaching your plants. Often, the few stragglers that do start to feed on your plants will not be causing enough damage to be worth mentioning … or can simply be controlled by hand-picking.

Think too that your vegetables will have grown considerably by then. They are no longer tender young seedlings very subject to insect damage, but well-developed plants better able to cope with a bit of insect presence.

Crop Rotation Is Mandatory

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You need to practice crop rotation if you want to create an effective insect barrier. Source: www.westcoastseeds.com

For this technique to be effective, you always have to rotate your crops. Otherwise, when the insect digs its way out of the ground in spring after overwintering at the base of last year’s host plant and you plant the same vegetable in the same spot and then plop a row cover overhead, the pest will be trapped inside the insect barrier. Thus, you’ll be supplying it with a fresh and readily available supply of its favorite plant!

However, if you practice crop rotation instead, you’ll be planting the host plant in spot where the plant did not grow the previous year and where the insect pest therefore did not overwinter. As a result, if you install row cover over a crop growing in a different section of the garden, you’ll effectively keep the pest entirely at bay.

Longevity

Under normal conditions of use, you can expect floating row cover to have a useful life of about 4 years.

No Harmful Insecticides Required

Of course, one main benefit of using row cover is that you won’t have to repeatedly spray potentially harmful and disruptive insecticides, resulting in less work for you and a break for the environment.


Improved results, reduced effort? Floating cover is just about the perfect tool for the laidback gardener!

Rhubarb: for the Patient Gardener

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20180517A blog.pennlive.com Des doryphores (bibittes à patate) bien frustrés! Ils peuvent voir et sentir leur plante-hôte, la pomme de terre, mais ne peuvent pas l’atteindre. .jpg

Rhubarb is a huge plant and very slow-growing. You likely won’t be harvesting it for at least three years after you plant it. Source: blog.pennlive.com

Rhubarb is a rather curious plant. Since it’s grown for its edible leaves (actually, we consume only the leaf stalk or petiole), gardeners consider it a vegetable. But, in the kitchen, its tart sweetness means it’s usually used in desserts (pies, crumbles, cheesecakes, stewed rhubarb, etc.) and preserves (jams and jellies), so many cooks classify it as a fruit!

For the purposes of this article, though, let’s call rhubarb a vegetable. After all, if you’re reading an article in a gardening blog, you’re probably a gardener!

That said, rhubarb is still not a typical vegetable. Almost all vegetables we grow are either annuals or are treated as such, sown in the spring for a harvest the same season. However, rhubarb is a long-lived perennial that won’t even give you anything to harvest before the second or even third year.

A Look Back in Time

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The Chinese harvested, dried and ground up rhubarb root as a herbal medicine. Source: www.herbalshop.com

Rhubarb comes from Asia, possibly Siberia, but has been cultivated by the Chinese for at least 3000 years, although not as a vegetable. Rather, it was used as a medicinal plant, its roots having cathartic and laxative properties.

It’s believed to have been introduced to Europe via Turkey, having been carried there from China over the Silk Road, still for medicinal purposes. Moreover, the name testifies to this introduction, because the word rhubarb comes from the Greek rha barbaron, which means “barbarian rhubarb” (rha being the word for Greece’s native rhubarb species). Essentially, “barbarian” meant, in this case, “foreign,” an indication that it was seen as a novelty from a distant country.

Oddly, although rhubarb was cultivated as a medicinal plant for centuries, it is only since the end of the eighteenth century that it has been consumed as a vegetable … or as a fruit, if you prefer. Previously, it was considered too toxic for use in cooking.

The botanical name of garden rhubarb used to be Rheum rhabarbarum, the Siberian species mentioned. However, DNA tests have shown that most modern rhubarbs are actually hybrids, a cross between R. rhabarbarum and an unknown species. Thus, most taxonomists accept R. x hybridum as the proper botanical name for today’s plant, although some old cultivars might still be pure R. rhabarbarum.

Rhubarb is certainly an imposing plant, easily 4 to 5 feet (120–150 cm) high and 3 to 4 feet (90–120 cm) wide under average garden conditions. It bears a cluster of very large, medium-green, heart-shaped leaves, strongly ribbed, with very thick green or red stalks. At the end of spring, it produces tall and highly attractive flower stalks of white or greenish-white flowers.

Where to Grow Rhubarb?

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Rhubarb is just too big for many vegetable plots … but looks great in a flower bed! Source: www.self-reliance.com

Since we’ve (sort of) agreed that rhubarb is a vegetable, logically it ought to be grown in the vegetable garden. But that’s probably not the best spot for it. Its long-lived nature (it’s a perennial) and large size make it a poor choice for the traditional vegetable bed that is otherwise emptied and cleaned in the fall, then replanted each spring.

Its permanence means you can’t use a rototiller near it (if that’s your habit), plus due to its size and very dense foliage, it tends to shade out sun-loving neighboring vegetables. And a single rhubarb plant would more than fill a square-foot garden!

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Rhubarb is best used as an ornamental plant… that also provides delicious desserts! Source: www.seedforsecurity.com

I, like many long-time gardeners, have long since moved rhubarb to the flower garden where it resides, perfectly contented, among other perennials that share the same needs. And it is doubly suited to the flower garden in that its huge wavy leaves, often with red stalks, and its particularly fine panicles of upright flowers, make rhubarb a very attractive plant.

And while we’re at it, no, you don’t have to remove the flower stalk before the flowers bloom, despite the long-held puritanical belief that since rhubarb flowers are attractive and give joy, they should be destroyed. Nor does letting rhubarb bloom weaken the plant. Like any typical perennial, it can easily bloom yearly and still produce a whole cohort of fine leaves. You may, however, want to remove the flower stalk after the blooms fade to prevent any seeds from maturing, as they can result in an abundance of unwanted, self-sown baby rhubarb plants.

Planting and Care

Plant rhubarb in the sun or, failing that, in partial shade, in a rich, deep, relatively moist, but still well-drained soil.

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A so-called rhubarb “root” or “crown” (actually a division). Plant it so the buds are covered in soil. Source: www.quickcrop.co.uk

Usually, divisions, called crowns or roots, are sold in the spring, although autumn is also a fine time to plant them. Dig a hole wider than the crown and deep enough so the eyes (buds) will be eyes covered 2 to 4 inches (5 to 10 cm) deep, spacing the plants about 4 to 5 feet (1.2 to 1.5 m) apart. Mix plenty of compost or well-aged manure into the soil dug out. If the drainage is poor, consider planting in a raised bed. Set the division in place and fill with the enriched soil, then tamp down fairly firmly and water well.

An annual application of compost will suffice as a source of organic matter, but it may also be wise to apply an all-purpose slow-release organic fertilizer, following the dose recommended on the label, early in the spring, as rhubarb is a quite a heavy feeder.

Mulching, although not obligatory, helps keep the soil cool and slightly moist, much to the plant’s liking.

Other than the occasional watering in times of drought, rhubarb usually pretty much takes care of itself through the spring and summer.

Rhubarb Likes it Cool

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Rhubarb coming up after a long, cold winter. Source: www.mymngarden.com.

Rhubarb is a typical perennial in that it loses its leaves in the fall and needs somewhat of a winter to succeed: several weeks at less than 40° F (5 ° C) are necessary to stimulate healthy spring growth and it can easily tolerate temperatures as low as -40 ° F (-40 ° C) with no special protection, so it will readily grow in hardiness zones 3 to 7.

You can also grow rhubarb in (huge) containers if you can manage to keep it fairly cool. A half-barrel would be about the right size.

It’s not nearly as easy to grow rhubarb in mild climates (zone 8 and above), although extra-thick mulch and partial shade can lead to some success in cooler parts of zone 8. Sometimes gardeners in hot climates grow rhubarb as an annual, sowing seeds indoors under air conditioning in the summer and planting the seedlings out when temperatures cool off in the fall. The leaves won’t be that big, but there will be harvestable petioles. If so, harvest all the leaves you want between early winter and spring, when heat will do the plants in anyway, forcing you to start more.

When Things Go Wrong

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Division is straight forward: dig up the plant in early spring or fall and cut into sections, each with one to three eyes… then replant! Source: www.mymngarden.com

You can often let rhubarb grow pretty much on its own for 20 years or more, but if you see that yours starting to decline, which can happen as early as after 5 or 6 years under some conditions, it’s usually because it has produced several offsets and is starting to get too crowded. If so, don’t hesitate to dig it out and divide it: that will usually give it a new lease on life. You can divide and replant rhubarb in either spring or fall.

Rhubarb rarely suffers very seriously from pests. Also, since a bit of slug, flea beetle or aphid damage is not likely to affect the part you want to harvest, that is, the leaf stalk, you can simply ignore minor infestations. Diseases are more common and much more likely to occur on plants grown in soil that is too humid or spots lacking good air circulation. Usually, the treatment is easy enough: just transplant them into a more rhubarb-friendly environment!

Rhubarb From Seed

Although rhubarb is traditionally grown from divisions, you can also raise it from seed. Rhubarb seeds are not that widely available, but can be found in several specialist seed catalogs. If so, sow it in late spring or early summer for a harvest that will likely begin in its third or fourth year.

Harvesting Rhubarb

This is where patience, mentioned in the title, comes in. You’ll need it if you want to grow rhubarb, because, unless you’ve managed to purchase a full-grown rhubarb plant, you won’t have any harvest the first year from the divisions usually sown and likely not more than a leaf or two the second. It’s really only when the plant is well-established and growing bountifully that you begin harvesting, and that is usually in year three.

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Rhubarb harvesting is easy enough: twist a stalk free, then cut off the leaf blade and put it in the compost. Source: hunterbackyardveggiegrowers.com

From then on, though, you can harvest up to two thirds of the stalks each spring, leaving the smaller ones so the plant can replenish itself. Traditionally, you harvest rhubarb in the spring, when leaves reach their full length. It is better to pull each leaf free with a twisting motion, because by cutting with a knife you risk transmitting diseases.

Of course, that’s the age-old way, but you can in fact harvest rhubarb right through the summer and into fall if you didn’t do it in the spring. That’s how market gardeners manage to supply rhubarb stalks off-season. And in late fall, even if you did do a thorough spring harvest, all those leaves that the plant no longer needs and will soon be turning brown still have edible petioles and that’s kind of a waste, so I suggest combining fall cleanup with a second harvest in September (Northern Hemisphere), while the leaves are still green. True enough, the second harvest may be a bit tougher and bitterer (and require more sugar) if the summer was hot and dry, but will still be very tasty after a cooler, fairly rainy summer.

Forcing Rhubarb

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Rhubarb can be blanched by covering it in the spring, here with a traditional rhubarb forcing pot of terra cotta. Source: www.sciencesource.com

In some countries, rhubarb is traditionally blanched, that is, forced under cover so it grows with no light. This gives a slightly earlier harvest of pale growth that is sweeter than regular rhubarb. You simply have to cover the plants with an opaque container early in the spring. In fact, there are even rhubarb forcing pots, traditionally made of terra cotta, you can buy. Put them in place at the end of winter and leave the containers in place for about 6 to 8 weeks, until the leaves, still pale and yellow, start to expand inside, then harvest away!

Growing for weeks without light can be hard on the plant and usually rhubarb plants thus treated are given a year off with no forcing so they can recuperate. Even so, forcing rhubarb is in decline. I suspect gardeners are tired of going through all the extra work … and expense (terra cotta forcing pots are not cheap!)

You can also force rhubarb for a midwinter harvest by potting it up in the fall and growing it under cover. This technique is usually used by market gardeners who want to produce extra-early rhubarb for customers willing to pay a premium for the first rhubarb of spring, but the home gardener can do it too. If so, pot up a mature plant in the fall, but don’t bring it indoors right away: allow it to undergo at least a few degrees of frost outdoors. Then store the pot cool and dark, in a garage or root cellar for example, for at least two months, keeping the soil at least slightly moist at all times. Then expose it to gentle heat (about 15 ° C) and up the leaves will come. The stalks will be ready to harvest in about a month.

How Poisonous Is Rhubarb?

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Rhubarb: the stalk is edible and the leaf blade is poisonous… maybe! Source: www.cookinglight.com

Most gardeners know that you should only eat the stalk of a rhubarb leaf, never the blade, because it’s poisonous. But how poisonous is it really?

In fact, very little is known about the subject. The truth is toxicologists don’t even know what causes the toxicity!

It used to be said that the problem was oxalic acid … and indeed, a lot of sources still make that claim. While in low doses, as in rhubarb stalks, oxalic acid gives the crop a delicious acidulous taste, it becomes toxic when in too great a concentration. (As the saying goes, the poison is in the dose!) However, although rhubarb leaf blades are about twice as rich in oxalic acid as their stalks, they’re still not as rich in oxalic acid as other plants we regularly eat, like spinach or chives. You would need to eat many pounds of rhubarb leaf blades to suffer from oxalic acid poisoning!

There have been very few cases of poisoning due to eating rhubarb leaf blades (I could only find mentions of two) and neither was truly unambiguous. They might have been caused by something else. Some toxicologists suggest that the true cause of rhubarb leaf poisoning, if indeed it exists, might be due to the anthraquinone glycosides it contains. But no one really knows and toxicologists simply don’t go around feeding people potentially poisonous leaves to find out!

As a result, the cause of rhubarb leaf-blade toxicity and even its degree of toxicity remain essentially a mystery. The truth may one day come out, but in the meantime, I say don’t take a chance: eat only the leaf stalks!

You Can Compost Rhubarb Leaves!

One thing is certain: there is no need to worry about putting rhubarb leaf blades into the compost bin, despite the popular belief that because they are poisonous, they’ll harm the compost’s beneficial organisms. In fact, microbes are able to break down almost any natural toxin and besides, seem to absolutely adore rhubarb leaves, which they digest very quickly. You can even add rhubarb leaves to a compost pile that’s maturing a bit slowly in order to give it a boost!

Do Rhubarb Leaves Make a Good Insecticide?

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Rhubarb spray is a popular homemade insecticide, but it’s actual usefulness has yet to be confirmed. Source: www.canva.com & crazyforcrafts.wordpress.com, montage: laidbackgardener.blog

Decoctions of rhubarb leaves are a popular homemade insecticide. They’re made by boiling the leaves in water, then pouring the cooled and strained solution into a spray bottle along with a little insecticidal soap for better adhesion. Then you spray it onto insect-infested plants. It’s said to be especially effective against aphids.

Is rhubarb spray effective? Some people claim so, others have less success with it. I don’t think anyone has ever done a bonafide study, one that would, of course, include a control group, to check it out. If the idea of a homemade insecticide pleases you, try it and see.

I use a similar treatment in my garden. I dilute insecticidal soap in water, but skip the the rhubarb leaf decoction, and that works very well!

Varieties

For an atypical vegetable, you’ll find a surprisingly large number rhubarb cultivars, most available only from seed. I have no particular recommendations. Ideally, you’d visit a farmer’s market where you can do a taste test, then choose your favorite.

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‘Canada Red’ is one of the most popular varieties. Source: www.westcoastseeds.com

In the past, green-stalked varieties, like ‘Riverside Giant’ or ‘Turkish’, were the most popular, but these days, rhubarb with red stalks, such as ‘Canada Red’, ‘Valentine’ or ‘Macdonald’ have definitely taken over the market. The popular variety ‘Victoria’ is sort of half and half: red at the base, green at the top.


Enjoy growing this charming, easy-to-grow plant and savor your first stewed rhubarb … in about 3 years’ time!20180517A blog.pennlive.com Des doryphores (bibittes à patate) bien frustrés! Ils peuvent voir et sentir leur plante-hôte, la pomme de terre, mais ne peuvent pas l_atteindre.

When Stems Change Color

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In the foreground, the red stems of the reversion; in the background, the yellow twigs of original dogwood, ‘Bud’s Yellow’. Source: laidbackgardener.blog

I made a surprising discovery at snow melt this year: the bark of one of the suckers (offsets) of my dogwood was not the same color as the original plant!

The plant in question, yellow twig dogwood (Cornus sericea ‘Bud’s Yellow’, which some authorities place in the look-alike species C. alba) is grown for its attractive yellow stems, especially visible in winter. The original species, though, has stems that turn red in the winter. ‘Bud’s Yellow’ originated as a yellow-stemmed mutation of the normally red-stemmed species (called, of course, red twig dogwood). However, my offset has gone back to the red coloration of its ancestor!

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A different reversion: the normally bicolor leaves of variegated ground ivy (Glechoma hederacea ‘Variegata’) have resumed the original entirely green leaves of the species … and the reversion is already starting to take over and smother the variegated part. Source: laidbackgardener.blog

This kind of mutation (and yes, it is a mutation!) is called a reversion: the plant has returned to its original form. Reversions are actually quite common, most often seen in plants with variegated leaves or bi-colored flowers. Part of the plant starts producing “ordinary” leaves or flowers. This is the first time, however, that I’ve heard of a reversion in bark color.

Normally, you’re supposed to prune out reversions to preserve the attractive qualities of the cultivar. That’s because reversions are often more vigorous than the cultivar and tend to take over and crowd it out. But I think I’ll keep mine. It seems to me that as the yellow and red twigged plants mingle over time, the result will be quite attractive.

Nature: always full of surprises!20180516A HC