As you harvest your root and leaf vegetables, your summer garden can start to look a bit empty. But that needn’t happen. In fact, it’s not even a good idea to leave gaping holes in a vegetable bed, otherwise the weeds will simply settle in*. It’s much wiser to sow other vegetables, fast-growing ones, to fill the gaps. And the benefit is you can then often double your harvest!
*Another possibility is to cover the empty spaces with a thick mulch. That won’t give you more vegetables, but it will at least prevent weeds from taking over!
Sowing Crops Successively
Starting second, third or even fourth crops in the same spot, one after the other, is called succession planting, as one crop follows another, in succession. Just sow fresh seeds in the spaces left vacant by the harvesting of the previous crop. Of course, the spot will still need to be reasonably sunny. Some vegetables, such as tomatoes and cabbages, grow wider and wider as they mature and so shade the soil all around them. That means they aren’t necessarily the best companions for sun-hungry seedlings. Even so, in heat of summer, many leaf vegetables, especially, do appreciate some shade, so a little help from taller neighbors is not necessarily a problem.
The Influence of Climate
Obviously, there isn’t enough time in areas with short-summer climates for succession crops of slow-maturing vegetables, including such fruit-bearing vegetables such as tomatoes and eggplants (aubergines), that often require 4 to 5 months to go from seed to fruit. However, most root vegetables and leaf vegetables can easily provide at least one second crop per summer. Certain vegetables, such as lettuce, spinach and radish, grow so rapidly they lend themselves to several successive sowings during the season, every two weeks all summer long, thus ensuring sure your family has fresh veggies to chomp on throughout the summer.
Even in the case of slow-to-mature vegetables, you can still do a second sowing if you only intend to harvest the leaves.
In the case of leafy greens, that’s only logical. No, you might not have enough time to see head lettuce ripen fully and form a dense head, for example, but you can still harvest it at will as “baby lettuce”.
That isn’t as clear in the case of root vegetables … until you think most can also be harvested as “baby” vegetables, plus have edible leaves. In most colder climates, for example, onions sown in August wouldn’t have time to produce a bulb by fall, but can still be grown as green onions. And you can hedge your bet with other root vegetables, even if you cut things a bit close timewise. With beets, carrots and turnips, for example, even if their root won’t likely have time to reach its maximum size, it will still make great a baby vegetable, plus will provide delicious and healthy leafy greens for the table.
For successive sowing, it’s useful to have in mind the approximate first fall frost date in your area. Where I live, I usually calculate I have until mid-October before frost is likely (that’s a full month more than it used to be 40 years ago when I expected a frost in mid-September!). With that date in mind, you can then count backwards to see if you’re likely to have enough time to produce a given crop.
You’ll then find the following list useful:
Weeks to Harvest
- Arugula – 4 weeks
- Basil – 8 weeks (baby leaves, 4 weeks)
- Beet (beetroot) – 8 weeks (baby beets, 4-5 weeks)
- Bok choy (pak choi) – 7–8 weeks (baby leaves, 4 weeks)
- Bush bean – 8 weeks
- Cabbage – 8 to 12 weeks (baby cabbage, 6 weeks)
- Carrot – 8–10 weeks (baby carrot, 6 weeks)
- Coriander (cilantro) – 4 weeks
- Dill – 4 weeks
- Endive – 8 weeks
- Green onions (from seeds) – 6 weeks
- Green onions (from sets) – 3 weeks
- Kale – 8 to 12 weeks (baby leaves, 6 weeks)
- Kohlrabi – 6 weeks
- Lettuce – 8 weeks (baby leaves, 4 weeks)
- Mizuna (and other mustards) – 8 weeks (baby leaves, 4 weeks)
- Parsley – 6 weeks
- Peas – 8 weeks
- Round radish – 4–6 weeks
- Spinach – 5–6 weeks (baby leaves, 2 weeks)
- Summer squash – 8 weeks
- Swiss chard – 10 weeks (baby leaves, 4 weeks)
- Turnip – 6 weeks
In Mild Climates
The list above was prepared with gardening in fairly short-season areas in mind. Obviously, successive planting opportunities are much greater in areas with long summers (in general, hardiness zones 8 to 12), where in fact there may be no frost at all, or maybe not until well into winter. Here, you can start succession crops of almost any vegetable, although they may mature less quickly under the shorter and cooler days of late fall and winter. You can more or less rely on the days to maturity indicated on the seed packet, then, with your frost date in mind (if you have one), count backwards to see if there’s still enough time to sow.
Keeping Seedlings Cool
If, in spring, it’s all about waiting until the soil warms up enough for good germination, in midsummer, heat will not be such a good thing, as few seedlings like really hot temperatures. In sweltering heat (85 ° F/30 ° C and above), it can be wise to delay planting by a week or so. You can also sow the seeds a little deeper than usual and water a bit more assiduously, thus keeping the sprouting seeds a bit cooler. Or sow summer vegetables indoors, if it’s cooler there, then transplant the seedlings outdoors when the heat wave is over. Once the seedlings are about 3 inches (8 cm) tall, start mulching them, as mulch also greatly helps keep the soil cooler.
When Early Frost Threatens
So, you took a chance and calculated that your garden ought to be frost-free until October 25th, but then the weather station announces a risk of frost in early October? That does happen some years. If so, remember you can easily protect plants from an early frost by covering them overnight with a blanket or sheet raised on stakes … or simply by turning on a sprinkler in the early hours of the morning (usually the moment frost hits). So act like a scout and be prepared!
Succession sowing: easy to do and so rewarding! Get out and try it today!