What to plant after early summer crops

Here’s what to plant and how to keep your vegetable garden going strong through the summer into autumn

Keep your garden growing strong throughout summer

Summer is well under way and, if you’re lucky, many of your late spring and early summer vegetables are ready to harvest. While some of the longer season fruits and vegetables like peppers, tomatoes, winter squash, and the like, will continue to grow and produce, many others will flower, fruit and die back.

As those early summer crops clear out, they’ll make room for a second round of fruits and veggies, which can be every bit as bountiful as the first if you take a few precautions.

The difference between early and late summer

There’s still plenty of warm weather ahead (76 days until Autumn and 90+ until mid-October as I write this), but the middle and later parts of summer present special challenges to the garden that you don’t have in early summer or late spring. If you’re aware of those, you can take steps to minimize their impact, and help your late summer crops thrive.

Temperatures are higher across the board – Not just air temperature, but soil temperature as well. Most plants can deal with a fair amount of heat in the air, but when the soil gets too hot, it really hurts. Excessive heat reduces the ability of the roots to wick water and nutrients into the plant. More importantly, it reduces the activity of soil microbes which provide the nutrients the plant needs.

Sunlight is more intense – In summer, the sun is high overhead, which means solar radiation (and the heat it creates) has less atmosphere to pass through to reach the ground. The increase in solar radiation not only makes plants more susceptible to sunburn, but it also means plants have to work harder to absorb water quickly enough to prevent leaves from wilting in the heat.

Days are getting shorter – once the summer solstice has passed, days start getting shorter. Early in the season this doesn’t mean much, but as summer goes on, those days shrink by minutes and hours, and trigger the plant to start flowering and fruiting more quickly than they would if the days were getting longer. Flowering and fruiting require a lot of energy; energy the plant would divert into growth if autumn (and winter) wasn’t on the way.

With these conditions and their impact in mind, you can choose the right plants for your later summer crops as well as take some steps to ensure they thrive.

Choosing crops for mid and late summer

Since summer is already in full swing, we don’t need to worry about starting plants indoors because the soil isn’t warm enough or to protect them from frost. You can direct-sow nearly everything.

Good choices for mid-to-late summer:

• Beans
• Corn
• Eggplant
• Melons
• Peppers
• Squash
• Tomatoes (determinate)

Avoid leafy vegetables like lettuces and greens, brassicas (broccoli, cauliflower, cabbage, etc.), and root crops (carrots, potatoes, onions. etc.). They’re hard to maintain in the heat and tend to bolt quickly. These are all better for early autumn planting.

When choosing the variety to plant, you want to pay attention to how many days to harvest the variety takes.

Here in San Diego (USDA zone 9), our day length shortens by only an hour or so between mid-summer and fall. Moreover, our hottest days don’t actually arrive until the very end of summer and early autumn when the Santa Ana winds arrive, so we can plant things that will take 90 days or more to mature.

On the other hand, if you live farther to the north, your day length and temperatures (especially night time temperatures), may drop 20% or more, so you’ll want to look at crops that mature in 75 days or less.

If you don’t have a lot of time, or your weather gets unpredictable later in the season, young plants from your local garden center or nursery are also a good option. They can save you upwards of 30 days or more.

Keep in mind if you’re transplanting started plants into the garden, they will need a little extra protection until they’re established. Read below to see how to provide it.

Ensuring a good late summer crop

As I mentioned earlier in this article, the biggest challenges in the late summer garden are the intense sun and the heat. The sun can burn both leaves and fruit, and too much heat will not only stop plants from flowering, but affect their ability to take in water and nutrients as well.

Sun protection

Giving tomatoes shade from the mid-summer sun with landscape burlap

To provide protection from the intense summer sun, you want to give your plants some shade.

Personally, I find plain old, loose weave landscape burlap fabric to be the best. It’s cheap, 100% organic, allows air to easily pass through, and blocks around 30% – 50% of the sunlight. That might sound like a lot, but it’s not. It’s really about the UV equivalent of full sun in mid spring or fall, which is plenty for healthy plant growth.

An alternative to burlap is shade cloth. It’s made from plastic and woven to densities that block anywhere from 30% to 70% of sunlight.

The advantage to shade cloth is that it doesn’t absorb water like burlap, so you don’t have t o worry as much about supporting it to keep it from crushing the plants. The disadvantage is the plastic will degrade under UV sunlight exposure and shed tiny plastic particulates into your garden. It can also tear in windy conditions.

One other way to provide shade for your crops is to grow sun-loving vining plants over your beds. Every summer I grow a vertical gourd garden over my western-most raised beds. Gourds love sun and heat, and their big leaves do a great job of shading a bed that would otherwise spend the day in the blazing desert sun.

Soil protection

A good mulch under plants will save water and protect soil

The best way I’ve found to shield the soil is with a 1/2-3/4-inch layer of fine mulch or leaves. That helps moderate soil temperatures and keeps more water in the ground where your plants can use it.

You can use a coarser mulch if you have to, but my experience is insects like beetles, sow bugs, and similar ground dwelling critters will hide out in it, often nibbling your plant’s stems and roots.

Also, use a lighter color mulch if you can. Dark mulches absorb more heat, whereas the lighter ones reflect it. Personally, I have a big podocarpus (Chinese pine) tree that provides an endless supply of small, tan-colored leaves perfect for mulch, but pine needles, straw and similar materials work equally well.

Fertilizer
Finally, the one other thing you want to make sure of, is that you’re providing your crops with plenty of food. Summer fruits and vegetables tend to be heavy feeders, and grow very fast, so they’re pulling nutrients from the soil at a higher rate than plants in the cooler seasons.

The best way to ensure you mid-to-late summer crops have what they need is to make sure you have good, rich soil with plenty of compost going into the season. Around mid-summer you can dress your beds with a little extra compost or add a little dry, all-purpose fertilizer to the soil to keep them fed through the rest of the season.

If your plants start to look a little yellow or limp later in the season, use a liquid fertilizer like compost tea or fish emulsion to give them a quick nutrition bump.

Ending the season

As the summer draws to a close, you might also want to think about a nitrogen-fixing transitional or cover crop to take you into autumn and help the soil recover over the winter.

Where I live, I can plant bush beans – many varieties of which will grow well in the shorter days and cool nights of autumn. If you’re in a chillier area where frost starts to show up in October or November, you can try peas, clover, or alfalfa. All will do well until extended freezes set in. You don’t even have to trellis the peas. Just let them sprawl across the ground and pick the pods as you go.

Once the plants die back, just leave them in place. If you pull them, all the nitrogen they trapped in their roots will be lost. Turn the remaining plant matter back into the soil in early spring and you’ll be off to another great start of the gardening season.