Continuing our series on extending the harvests in your garden, this week’s post will be about extending the growing seasons for summer and fall crops. Many of the most beloved vegetables like tomatoes and peppers have to be grown in warm weather, but their long maturation time can make it difficult to get more than a single harvest before the first frosts hit.
As we talked about in the last post, the key principle for extending the season is to control the temperatures of the air and the soil. If the temperature drops too low, either the seeds won’t sprout or frost will kill the plant.
Frost kills plants because it freezes the water inside of the cells and causes them to rupture. Cool-weather plants have a neat trick where they convert some of their starches to sugar when it gets cold. The sugar drops the freezing point of the water and prevents ice crystals from forming. It also makes the plant taste sweeter, which is why some people wait until after a frost or two to harvest fall greens.
Summer annuals don’t have this defense mechanism. In fact, many of them don’t like the temp to go below 50 degrees and will refuse to sprout at all if the earth is too cold. Therefore, if you want a longer harvest season of summer vegetables you’ll need to plan ahead.
Starting earlier in Spring
The common way to get a head start on summer crops is to grow seedlings indoors and transplant them later when the weather is warm. This requires a lot of additional equipment, electricity, and know-how. I personally believe it’s better to start your crops outside from seed if possible.
Unless you have a heated greenhouse, don’t attempt to start summer crops outdoors until after all chance of frost has passed. The sun alone won’t be enough to raise the temperature enough to germinate summer crops. Not even a hoop house will work until after the frost. If you did build a hoop house you can easily get a jump on summer crops by moving the structure to a new spot once your hoop house is too hot for your greens.
Measure the soil temperature in the new location each morning until the right germination temperature is reached, then plant. Keep an eye on water and temperature as the weather warms until the plants can live without assistance. It’s a good idea when using an enclosed structure to let the new plants get a few hours of exposure to the wind if the weather is amicable. Plants use the wind to build stronger stalks.
Ending later in Autumn
It’s easier to grow summer crops earlier than to try to grow them later down the line. You’re in a race against the first frost to get another harvest out. That being said, it can be done if you plan ahead. You can extend the harvest 2-4 weeks after the first frost date in many regions.
Know how long your crops will take from planting to harvest. For example, a tomato plant can take anywhere from 50 to 90 days from germination to harvest. Hot peppers can take 150 days! Also, after that first harvest date a plant may continue to produce for a month afterward. If the time frame to grow the plant is going to take you beyond 2-4 weeks past first frost, it’s not worth the effort unless you have very mild winters.
First, stagger your plantings of the same crop every two weeks rather than just one or two big sowings. This gives more plants a chance to survive all the way to the end of the harvest. This is also a good way to avoid being buried in a single crop before you can eat or can it all.
Second, once the low temps start dipping below the preferred germination temperature for your summer plants, start putting a cover over them at sundown. This cover needs to reach all the way to the ground, much like covering yourself up in a blanket keeps you warm. In fact, sometimes the easiest way to do this is to throw a quilt over your trellis or tomato cages and weigh it down with bricks. You can also do the same for non-pole crops by putting a hoop house over them and then throwing the quilt over that. This will hold valuable heat in during the night and keep them growing strong. Remove it during the day so they can get sun.
Third, you can also add a light layer of straw mulch over the plants at night to hold in additional warmth. Again, remove it during the day to allow light to reach the leaves. If you follow these tips and keep a careful eye on the weather you should be able to get extra harvest.
- Cold air likes to sink. If your garden is in a depression it may get colder faster than the average air temperature. Pay attention to your land and put that blanket up earlier if you need to.
- Take notes! Every region and crop is different. If you keep notes of what died early, what survived, what you did, and the dates you’ll be better prepared next year
- If you have the space, consider learning how to store your summer crops in a root cellar. If you can get that skill down you can get yourself some extra insurance. The alternatives for urban dwellers are freezing, canning, drying, fermenting, etc.
Remember, resilient communities do what they need to do to ensure a healthy supply of food. If the supermarkets ever go empty you’ll want to know what you need to do to contribute. Start growing your gardens now and get the skills you need before things get difficult later!