If you are planning on planting a fall vegetable garden, you must start planting it in the summer.
I know – it sounds a little strange, planting an autumn garden when it was 95°F, we still have a tendency to our tomato and squash plants. However, autumn crops need cool weather to thrive, and they must go to the ground between the middle of summer and the end of summer in order to mature before winter arrives.
Read more: Autumn Crops I recommend planting in the middle of summer
However, this is also the hottest time of the year, and requires a lot of attention to things, whether you are sowing seedlings directly into your garden. You could end up with a few inches, a bolt too early, or a stunting plant that doesn’t pass through crispy leaves. (I went there, I did that.)
If you want to get a cool weather crop to a good start, the first thing to know is whether the plant can be sown directly on the ground, or whether it needs to start with seeds indoors (or buy it as a transplant from a nursery).
Direct sowing crops
Most root vegetables (carrots, beets, radish, turnips, etc.) and the lush greenery of quick breeding (kale, arugula, mizuna, bokuchoi, etc.) are the easiest to be consumed directly in the garden. The seeds germinate quickly in warm soil and the flavor improves as the plants mature in cool autumn weather.
To ensure they don’t immediately tighten the bolts or suffer in the heat, here’s what I recommend:
Try to sow seeds in the shade (or in between) of tall summer crops. Push the seeds a little deeper into the soil so that they don’t dry too quickly. Turn on hand water or sprinklers every day, especially during very hot or dry climates, to ensure that the soil (and seeds) is evenly moist. (Drip irrigation is generally not effective for seed germination.) If the seedlings are a few inches tall, add mulch. There is water for a longer period of time so that the roots grow deeper into moist, cool soil (rather than being near dry and hot surfaces). If your garden is in the sun all day or exceeds 90°F after a few weeks, use a shady cloth to provide seedlings from the daytime heat.
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Transplant
Some crops (such as broccoli, cauliflower, cabbage, Brussels sprouts) take a long time to mature, and if you live in a cold climate, you need extra time to grow if you want to harvest before a winter hit.
Other crops (such as lettuce, radicchio, mach, minor lettuce, etc.) do not germinate in too warm soil, so once they harden properly, they start from the inside and are transplanted outside.
Related: Most ideal soil temperature for seed germination
You can count back several weeks from the first frost (if you’re not sure when, check the frost date here).
If you want to start at the Garden Center for ease of purchase, make sure your start is not on the brink of bolts and is not root bound. In many cases, garden centers run sales to move the remaining inventory during this time of year.
When it’s time to plant outside, here are some ways to help with transplants:
Make sure all implants are cured properly by starting with a few hours of mottled sun in the morning and gradually increasing the time and intensity of sunlight every day. Check your predictions and choose a mild day for your transplant. Ideally if it’s cloudy and below 90°F. (Bonus points If there’s a little rain after you plant it is a bonus point.) You can plant it late in the afternoon or evening to settle down before the plants get hot again. Liquid kelp fertilizer (such as this) is used during implantation to reduce transplant shock, support root growth, and stimulate soil microorganisms. Water thoroughly (and deep) but not above water. Add a few inches of mulch to retain moisture and adjust soil temperature. Use a shaded cloth over a new implant to protect against heat stress. After a week or two, remove the shaded fabric so that the plant can grow completely in the sun. (As the sunlight time begins to fade and the arc of the sun drops on the horizon, plants will need all the sun they can get!)
Autumn crops can withstand light frosts as we move into autumn, but many people can also handle the freezing temperature with a little protection. If you want to extend the season and harvest vegetables in December or January, follow our guide on how to grow until winter without a greenhouse.
