Time for a Tree Inspection


When leaves have mostly fallen from your trees, it’s time to give them a good going over. Source: A melbournechapter.net & svgsilh.com, montage: laidbackgardener.blog

The disappearance of leaves from deciduous trees in the fall is often seen by home gardeners as the end of the horticultural season, but it’s also a golden opportunity to study your trees’ condition. Bare of foliage, their entire structure is visible, allowing you to see any flaws. So, a quick annual tree inspection tour, just to make sure everything is fine, is always a good thing.

Structural Problems

The most obvious problems usually have to do with weak, damaged or dead branches. Some branches may have snapped or bent and need removing. Others rub on neighboring branches, weakening and, eventually, killing both. Ideally, one or the other really ought to be removed.

Sometimes, you see clusters of weak branches all growing from about the same point, a probably as the result of an earlier poor choice in pruning. You’ll have to prune off all but one branch (probably the healthiest, straightest one) to give it a chance.

You can also remove any suckers (upright branches with no secondary stems) if you see any. Or there may have a very vigorous upright branch that is threatening to become a second trunk and that usually leads to a weak fork that can tear off and seriously damage the tree. So remove that as well.

Corrective Pruning

In all these cases, the solution is to do a little bit of pruning.

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If you can reach it, you can prune it! http://www.danskhusoghaveservice.dk

You can do the pruning yourself if the branches are near enough to the ground for you to be able to reach them, at least with a pole pruner. (Obviously, any time you remove a branch higher than your head, you should be wearing a safety helmet.) For out-of-reach or oversized branches, it’s better to have a certified arborist do the job. Avoid fly-by-night tree trimmers who often damage trees rather than helping them.

Also, over time, the lower branches of a tree sometimes start get in your way. Since you don’t want anyone to bump their head when walking under the tree, it is often better to “limb it up” (also called “raising the crown”) by removing the problematic lower branches and that’s something you can do yourself.

When to Prune?

To be completely honest, the time of year when you prune really doesn’t make a lot of difference. Yes, many experts say late winter or very early spring is the best time, while late fall/early winter is the second-best choice. In fact, the easiest thing to do is simply to prune when you first see the problem, before it gets any worse.

Two Typical Pruning Scenarios

When you simply want to shorten a branch for whatever reason, just cut it off slightly beyond a secondary branch pointing in the desired direction. The latter will take over and replace the original one, thus preserving the tree’s natural symmetry.

Removing a branch entirely, right back to the trunk, is a different situation. Doubly so if it’s a major branch. If you simply saw it off from above, the branch will likely tear loose as you near the end, pulling off a strip of bark as it falls, thus damaging the tree’s structure. Fortunately, there’s an easy way around this.

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Source: Claire Tourigny, from the book Les 1500 trucs du jardinier paresseux

First cut a notch under the branch, about 1 foot (30 cm) from the trunk and about ¼ to ⅓ of the way through. Then change position. Now saw from the top about 2 to 3 inches (5 to 7 cm) beyond the first cut until the branch breaks right off. It will now do so away from the trunk, thus avoiding any damage to it.

The final cut is the most important one, as you have to remove the stub. Cut as close to the trunk as possible, but without damaging the branch collar, the swollen bump seen at the base of the branch, because it’s from the collar that the new cells designed to cover the wound with fresh bark will form.

Finally, no, there is no need to cover the wound with pruning paint. It’s actually bad for the tree. Read Garden Myth: A Tree Wound Requires a Coat of Paint to understand why.

Bare Tree Leads to Other Discoveries

You may have other surprises when the leaves fall.

Often, you’ll find a bird’s nest, sometimes only a short distance from your front door, you never noticed in the summer, but that is visible now that the leaves have fallen. It will be empty in the fall and winter.

Or maybe you’ll discover a squirrel’s nest, which usually looks like a ball of dead leaves high up in the tree. In this case, the squirrel is likely still inside, as it’s a winter nest. You’ll discover that squirrels don’t actually hibernate. Although they spend much of the winter sleeping, they still come out from time to time to look for the nuts they buried in various hiding places earlier in the fall.

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Wasp nests are empty in the fall; the first frosts will have killed off their inhabitants. Source: USFWS Midwest Region, flickr.com

The other nest you’re likely to notice, looking like a greyish round ball in the branches, is a wasp nest. No need to panic: by mid-fall, the original queen and her workers will already be dead. The only survivor of the whole colony is the new queen and she’ll have left the nest, burying herself in the ground somewhere. She’ll wake up again in the spring and start building a new nest in another location. So, since the old nest is empty, if you want to recover it as a decoration, go for it! Otherwise, the nest will simply disintegrate over time.

Signs of Disease and Insects

So much for pleasant discoveries. Others are not so encouraging.

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Black knot disease is revealed when the leaves fall. Source: http://www.edmontonlandscapingoutdoorspace.com

Probably the most disagreeable discovery you make when a tree is free of leaves is black knot disease (Dibotryon morbosum, syn. Apiosporina morbosa). This disease of plums and cherries (and occasionally other stone fruits) attacks the tree’s branches: you’ll discover an elongated black mass covering part of a branch. Black knot acts much like a cancer, cutting off the flow of sap to the affected limb and eventually causing its death even as it spreads to other branches. Sadly, once you discover black knot in a tree, it’s probably doomed: at most you can extend the tree’s life by removing the nodules. Read The Cancer of Plums and Cherries to learn how pruning can be of some help.

Whether you decided to prune or not, I suggest you plant a replacement tree (and not a cherry or a plum!) in the spring. When your tree finally does die, its replacement will have already reached a decent size.

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These innocent-looking bumps are scale insects. Source: growingsmallfarms.ces.ncsu.edu

You may see other odd growths on the trunk and branches. Sometimes they’re harmless, like lichens and moss, sometimes they are serious diseases, such as crown gall disease (Agrobacterium tumefaciens), and sometimes the growths are caused by insects. Tiny bumps on the bark, for example, may well be scale insects.

Whatever causes the growths, you’ll have to identify the problem before appropriate treatment can be found.

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The perfect day for a tree inspection! Source: http://www.dpreview.com

Take your inspection tour on a beautiful late fall/early winter day, when you feel like taking a bit of a stroll outdoors anyway. And remember, this annual checkup is not only free, but often helps prevent very serious problems in years to come.


Clean and Sharpen Garden Tools Before Winter


Thoroughly clean your garden tools before winter. Source: gardencontainer.wndrs.com

To work effectively, garden tools should always be clean and well honed. Even a shovel doesn’t dig as well when its blade is blunt. And leaving tools dirty can lead to rust. So, get in the habit of cleaning and sharpening your tools at least once a year, normally before putting them away for the winter.

Start by Cleaning

Thoroughly rinse the tools that have been in contact with soil with a jet of water to remove most stuck-on soil, then wipe the entire surface with a cloth soaked in soapy water to remove other dirt. It may be necessary to scrub with a wire brush to remove truly stubborn clay.

Then Sharpen

Any tool with a sharp surface needs to be sharpened occasionally.

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AnySharp Multi-Tool Sharpener. Source: www.hsn.com

I recently tested a new sharpener (new for me at least) called the AnySharp Multi-Tool Sharpener In fact, it has two sharpeners. The first one sharpens knives, scissors and pruning shears, while the second is designed to clean and sharpen almost any other garden tool: shovel, lawn mower blade, trowel, hatchet, etc. Easy to handle, it takes only two or three strokes to get the job done.

If local retailers don’t offer this sharpener, you can order it from the manufacturer, AnySharp, for $18 US. It’s also available on Amazon.



Lightly coat the blade surface in oil. Source: ziraatyapma.blogspot.com

To finish, apply oil—even vegetable oil!—to prevent rust from setting in over the winter. Just soak a cloth in oil and rub it lightly it over the metal surfaces. You can also spray the tool with oil.


Garden tools are not harmed by cold and can easily spend the winter in an outdoor shed.

So, a little cleaning and sharpening before putting your garden tools away for the winter will guarantee you years—sometimes decades!—of extra use: a little effort well worth investing!

What to Do About Bracket Fungi?


Source: Louise St. Cyr

Question: My mature tree is infested with strange growths. What should I do?

Louise St. Cyr

Answer:What you’re seeing is a fungus known as a bracket fungus or shelf fungus. Scientifically, it’s called a polypore. It’s one of the most common mushrooms on the planet, with at least a thousand species. They are characterized by a fruiting body (the part that is readily visible and produces spores) in the form of a shelf, often called a conk. Bracket fungus fruiting bodies are often tough and woody and can live for years, although some are annual. If you examine the underside of the bracket, you’ll usually find many tubular pores, hence the name polypore (multiple pores).

Most bracket fungi found on living trees only live on and decay the heartwood; they do not infect and kill the living parts of the tree. You’ll also find bracket fungi on stumps, logs and fallen branches where they continue their vital role of decomposing wood.

Hidden Decomposition

When you find bracket fungi on a tree, the mushroom has already been at work inside the trunk for a long time, usually years. Its vegetative part, called the mycelium, is made up of filaments (hyphae) that run through the heartwood of the tree, digesting it gradually, leading it to rot and, eventually, disappear. Your tree will then become hollow, at least in part. True enough, some trees do succeed in sealing off the decomposing sector, thus limiting to the spread of the mushroom, but you can usually assume the fungus has already spread widely through the heartwood by the time you notice its presence.

There is nothing to do to stop the process. The mycelium is essentially the real fungus and it’s out of reach, in the heart of the tree. There is no treatment to control it. The visible part of the mushroom, the fruiting body, only serves for reproduction. Even if you remove it, the decomposition will continue inside … and moreover, new brackets will grow back.

Do You Need to React?

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Even a hollow tree can live for decades. Source: krapooarboricole.files.wordpress.com

Not necessarily. The heartwood of a tree is always dead anyway. There is only the bark and a thin layer of whiter, softer wood under the bark (sapwood) that is actually alive. Although heartwood is dead, it remains useful because it helps the tree to better withstand the wind, but its decline or disappearance does not always have unfortunate consequences: you often see trees infested with bracket fungi and even completely hollow that are still very solid. Often, they continue to live for 20, 40 or even 60 years after the discovery of the first brackets.

To check whether your tree is still structurally sound, you should consult an experienced arborist. If he thinks it is weak and that it may do damage when it falls, have the tree removed. If not, let it continue its life. After all, not only might it still last years as an ornamental element on your property, but hollow trees and even dead ones are highly useful to wildlife.

Cats Can Carry Irritating Cactus Spines


Source: www.missioncats.net, weedecor.com& http://www.kisspng.com, montage: jardinierparesseux.com

Many years ago now, my wife and I began suffering from a mild but annoying form of dermatitis: reddish, itchy hands, arms and lower legs. It was really quite mysterious: we couldn’t think of any likely cause.

Then one day I noticed our cat, Nounouche, sidling along a windowsill, brushing up against plants there as cats are wont to do. And among the plants he was rubbing against was a cute little prickly pear cactus, Opuntia microdasys, sometimes called bunny ears cactus. Bingo! I instantly knew what the problem was!

Irritating Glochids

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Most opuntias bear only a few of the longer, highly visible spines… but the tiny ones on the areoles are also a concern. Source: Sheldon Navie, lucidcentral.org

Prickly pears or opuntias (Opuntia spp.) are unusual among cacti in that they produce two types of spines. Long, fierce, painful ones that dig into the skin, draw blood and yelps and are very visible and, on the cushiony areole at the base of the vicious spines, tiny hairlike, barbed spines called glochids. While the long, nasty spines stay on the plant, glochids break off readily and work their way into the skin, causing itching and irritation that can, in sensitive individuals, last days, weeks or even months. You rarely recall running into glochids, as they seem harmless. But if you get any on your skin, you’ll remember the experience.

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The colorful cushiony areoles of Opuntia microdasys actually are covered with tiny hairlike glochids. Source: jinjian liang, flickr.com

It just so happens that O. microdasys is one of those opuntias that lacks any long, painful spines and, in fact, looks totally harmless, as the “bunny ears” name suggests. It only bears the easily detached glochids which can be red, yellow or white, depending on the variety. As a cactus collector, you soon learn to avoid touching O. microdasys unless you are wearing gloves.

A Feline Intermediary

What Nounouche was doing was picking up glochids when he rubbed up against the cactus, then transferring them to us when we petted him or he brushed against us. The problem was thus easily solved: the offending cactus was moved to another spot, behind other plants, where Nounouche couldn’t get near it. I honestly don’t think I ever told my now ex-wife the cause. Already she wasn’t too fond of me filling all available window space with plants!

Removing Glochids

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Glochids. Source: DaveC, Shroomery.org

Ideally, you’d only wear thick, long-sleeved gloves or use tongs when handling any prickly pear, but in case glochids do get to you, remove them quickly before they work their way into your skin. To do so, use sticky tape (duct tape is perfect), softly pressing the tape over the affected sector, then yanking it off. Individual remaining glochids can be removed with eyebrow tweezers, although you may need a magnifying lens to see what you’re doing.

Once they’ve worked their way into your skin, though, you pretty much have to wait until your body reacts, causing dermatitis then pustules, then eventually expelling them.

Itching Powder

Rumor has that opuntia glochids were once used as itching powder. I’ve heard that many times, but could never find any proof of it. Today’s itching powder (and who would use itching powder anyway?) can be made of all sorts of products, but not, apparently, opuntia glochids. You certainly wouldn’t want to get glochids in anybody’s eyes: they can cause blindness!

Edible When De-spined

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Prickly pears or tunas do have glochids, so be careful when harvesting and handling them. Source: John Tann, Wikmedia Commons

The fruit from some species of prickly pear (usually O. ficus-indica), sometimes called by its Spanish name “tuna,” is sold commercially. Such fruit will have been rubbed or burned to remove any glochids. If you grow your own (the edible types tend to be too big and too reluctant to bloom indoors to make good edible houseplants), probably outdoors in a very mild, dry climate, harvest the fruits with tongs or thick gloves and rub them with a brush under running water to remove the glochids. Lightly scorching them with a propane torch also works, but that’s not something you necessarily should be doing near desert-dry vegetation!

Young opuntia pads, called nopales, are also edible… after a treatment similar to opuntia fruits or simple peeling.

So-called spineless opuntias, like O. ficus-indica ‘Burbank Spineless’, may not have long, vicious-looking spines, but they do bear glochids, so handle them with care.

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Cute kitten, cute cactus, but never the twain should meet! Source: Dane Larsen, flickr.com

In fact, handle any opuntia or prickly pear with care: while some make look as cute as a button, they all pack a hidden punch!

How Garden Plants Adapt to Cold


Plants do best when they can acclimatize slowly to cold. Source: libreshot.com

If you live in a cold climate, you’ve probably noticed that the first time temperatures drop to 40°F (5 ° C) in the fall, you find it really cold. It takes a winter coat, a wool hat and gloves before you feel at ease outdoors. However, if in February (in the Northern Hemisphere), the temperature is “only” 40 °F (5 ° C), you find quite balmy and may even yourself unbuttoning your coat! Between October and February, you’ve acclimatized to winter conditions. But your acclimation will disappear as spring settles in. Thus, if there’s sudden drop to 40 °F (5 ° C) again in May, you’ll haul out the winter coat, hat and gloves again … and probably complain bitterly about how cold it is!

Plants Adapt Too!

Well, hardy plants have a similar process of acclimatization and deacclimatization. The short days and the gradual drop in temperatures of fall push cold-tolerant plants into deeper and deeper dormancy. They’re at their hardiest in the middle of winter. Then, in the spring, the plant acclimates again to warmer temperatures and gradually loses its resistance to cold. Thus, a balsam fir (Abies balsamea), one of the hardiest of all trees, one that won’t flinch at -40 ° F (-40 ° C) in January, will be seriously damaged at only -10 ° C in July. It has, by then, lost its winter hardiness.

How hardy plants adapt to the cold varies from one species to another. Some develop a kind of antifreeze that prevents their sap and cells from freezing, others reduce the amount of water in their cells (water expands as it freezes and can tear and kill cells as it does so), some lose their leaves in winter and others retreat completely underground. Most combine different methods.

The Ideal Situation

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Ideally, temperatures would drop gradually from early fall into winter. Source: M. Marquez, http://www.nps.gov, montage: laidbackgardener.com

In a perfect world (assuming a perfect world includes cold winters!), cold would set in gradually starting in September and temperatures would drop little by little from week to week. An Indian summer may be wonderful for humans, but it can seriously harm hardy plants, which can lose their resistance to cold if it lasts too long.

Where I live (Quebec, Canada), the fall of 2018 has been picture-perfect for plants so far: it literally has been getting colder week by week with no annoying Indian summer to set plants back. If this trend continues, the hardy plants in my region will spend the winter of 2018–2019 in excellent condition!

What Human-Imposed Winter Protection Does and Doesn’t Do

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“Winter protection” doesn’t really protect against the cold. Source: paysagesrodier.com

Did you know that “winter protection” (i.e. wrapping plants up for the winter), which I see many homeowners installing these days, actually doesn’t protect against the cold? Even if you wrap your shrubs, trees and evergreens in burlap or geotextile, or build a covered cage around them, night temperatures inside these protections are essentially the same as those outside.

Moreover, it’s important that these protections be light in color. Dark wrappings absorb heat during the day and can actually reduce the plant’s resistance to cold. When a really cold night follows a few days of unusual warmth, the plant can be severely damaged or even die.

So burlap, cages and geotextiles don’t keep the plants any warmer, but what they do accomplish is to minimize the drying effect of winter wind. They are therefore especially useful for plants that are freshly planted and not yet settled in or those that are planted in a very windy site.

Personally, I don’t use this kind of winter protection in my garden: it’s too much work for the slight advantage that it gives … when there is an advantage, that is; often, there is none. (I find many people wrap up plants that don’t need any protection!) In addition, winter protection tends to help plants poorly adapted to local conditions to cling to life. I prefer to use plants that like my conditions. If a plant can’t tolerate winter at my place, I’d rather it die quickly! I’ll soon find a hardier replacement. The right plant in the right place: always the best thing to do!

How to Really Keep Plants Warmer

There are, however, two “winter protections” that are very effective at protecting plants against the cold: snow and mulch.

To understand why, you need to know that the roots of most plants are much less hardy than their branches and leaves. They usually don’t need to be, as soil is normally warmer than the air above due to “bottom heat,” geothermal heat moving up from the depths of the earth all winter. But sudden drops in air temperature can cause deep freezing of unprotected soil, a disaster for plants.

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Snow is an excellent insulator. Source: Wendy Cutler, http://www.flickr.com

Snow helps by keeping cold air from penetrating deeply into the ground. It’s an excellent insulator, being mostly composed of stagnant air. For example, when the air is at a frigid 5 ° F (-15 ° C), for example, the soil below is rarely much colder than 30 ° F (-1 ° C) under a layer of 6 inches (15 cm) of snow.

The more snow there is in winter, especially when it arrives early and stays late, the better condition your plants will be in come spring.

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Mulch is a good an insulation as snow… but more reliable. Source: russellnursery.com

Mulch—a layer of organic matter covering the ground—acts in the same way as snow: it creates an insulating layer between sometimes extremely cold air and the soil below. Its advantage over the snow is that it is reliable: it doesn’t suddenly melt away in mid-January, leaving your plants exposed, as snow can do. Moreover, snow on top of a winter mulch makes an even more effective insulation: it’s a winning combination!

I mulch just about all my plantings with chopped leaves, ensuring the best winter protection that money can buy… Oops! I suppose I didn’t spend any money on my shredded leaf mulch, did I?

Whether you to wrap your shrubs for the winter or not is up to you, but remember the best winter protection is actually free: snow and leaf mulch!

Browning Leaves on an Indoor Avocado


Avocado leaves with dry brown edges are usually due to dry air. Source: cantikalami.club

Question: I grew an avocado tree from seed this summer and now the edges of the leaves are turning brown. Why? The plant is 30 inches (75 cm) tall and has only one main stem.


Answer: The avocado tree (Persea americana) rarely does very well under the conditions that prevail in the average home. True enough, it’s relatively easy to grow one from a pit harvested from a store-bought fruit and that’s kind of fun. Plus, it does grow vigorously at first, but it tends not to stay attractive very long … and that’s normal. Indoor conditions are not really much to the plant’s liking. It would really prefer full tropical sun and intense atmospheric humidity, things that are hard to give it indoors.

The plant most often shows its displeasure in the fall and winter, when its leaf edges start to turn brown and dry out, a condition that engulfs more and more of the leaf surface over time.

And the main cause is dry air.

The avocado comes from a humid tropical climate where the atmospheric humidity is usually at least in the 70 to 80% range and often well above that. Indoors, though, relative humidity drops seriously during the heating season. In many homes, it remains below 30% throughout much of the fall and winter. And when the air is too dry, evapotranspiration (loss of water from leaf cells) increases. Soon, the large but thin leaves of the avocado begin to lose water more quickly than the plant can replace it and when that happens, the cells begin to die, leading to browning.

Humidifier to the Rescue

To keep the leaves in top shape, you need to try increasing the humidity as much as possible and the easiest way of doing so is with a humidifier. If you can manage to keep the humidity in the 45–55% range (also, a good level for humans and pets), that will make a huge difference. Of course, this is far from the 70 to 80% the plant really wants, but at least it ought to keep all but the oldest leaves from browning at the edges.

A humidity tray can help too, although it’s more efficient on shorter plants. The humidity it gives off often diffuses into the air around before reaching the lofty leaves of indoor trees like the avocado.

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Spraying the leaves with water is just a waste of time. Montage: laidbackgardener.blog

And there is no point in spraying the leaves with water in an effort to increase humidity. The concept that spraying helps plants to cope with dry air is one of those garden myths that refuses to die.

For “perfect” growth (i.e. no browning at all), grow it in a humid greenhouse or seal your avocado tree inside a large clear plastic bag during the fall and winter. The humidity inside will be 80% and above, just perfect for your avocado. Yes, it will be able to breathe inside a sealed plastic bag. Just watch out for too much condensation. If that occurs, open the bag for a few hours … then seal the plant in again.

Note that, even if you increase the humidity, the damaged leaves will not turn green again, but rather new leaves will not turn brown. In other words, high humidity doesn’t cure browned leaves, it only prevents future damage.

Some Additional Suggestions

First, can I assume that your plant is growing in potting soil? If not, pot it up without delay. Many people start their avocado pit over a glass of water, but it won’t live forever that way. In fact, as soon as you see the first signs of root growth, you really should transplant it into a terrestrial environment.

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If you let the leaves of your avocado wilt, that too can lead to brown leaf edges, especially if the air is dry. Source: brbdyer420,www.houzz.com

After it has been potted up, regular, deep watering will be necessary. The root ball must never dry completely, because that too can lead to leaf browning. So, as soon as the soil seems dry to the touch, it is time to water again.

Also, hard water is not good for avocados. They prefer a more acid soil without excess minerals and for that reason, the water would ideally be soft. However, not only can tap water be hard, depending on its source, but the chemical treatments given to municipal water to keep it drinkable can increase its hardness. And hard water can also result in browning leaves, especially in combination with dry air.

Ideally, the water would have a calcium carbonate concentration of less than 60 mg/l: i.e., it should be soft. If your water is considered hard or very hard, it would be better to water your avocado tree with rainwater, dehumidifier water or distilled water.

Or Just Ignore the Problem

The good news is that even if you do nothing at all, the condition of your avocado tree should begin to improve all on its own in the spring, as the damaged leaves will eventually drop off and will be replaced by fresh, healthy leaves. And in the spring and summer, the air indoors in most climates is much, much more humid than in the winter: certainly at least in the 50% range. The result is that the new leaves should remain in fine shape … that is, until the next heating season.

Avocados: fun to start, but not such great houseplants. And they really hate dry air!