Category Archives: Garden Advice

Heat Stress in Plants

We’re into the hottest days of summer now. For many, it’s a bountiful time of year. You may be harvesting armloads of summer squash, tomatoes, cucumbers, green beans, and other favorites at this point in the season. Unfortunately, you may also begin to spot signs of heat stress in your plants, especially if you live in an area affected by prolonged heat waves. Recognizing heat stress and knowing how to prevent and stop it can improve your harvest.

What Does Heat Stress Look Like?

Heat stress can look different depending on the plant and local conditions. Here are a few common features you might see if plants in your garden are stressed.

Bolting

Bolting is when a plant goes to flower and usually becomes bitter and inedible. While bolting is a natural part of many crops’ life cycles, premature bolting is often a sign of heat stress. In hot weather, you may notice your broccoli, cauliflower, lettuce, and spinach bolting.

Wilting

While dropping leaves can also be a sign of disease, it’s often a sign of heat stress. If your plants droop during the heat of the day but perk back up in the evening, it’s probably the heat.

Blossom and Fruit Drop

Plants may drop fruit and blossoms in extreme heat to conserve resources for survival. You may also notice misshapen or unreformed fruit like cucumbers. Often these plants will recover after a heat wave passes.

Sunscald

Some crops, particularly tomatoes, melons, and peppers, may develop sun scald on the side of the fruit exposed to the sun. This may look like watery spots, blistering, or discolored spots. It often occurs in plants that have lost much of their foliage to disease. 

Blossom End Rot and Other Disease Issues

Blossom end rot can be annoying when you grab a tomato that looks perfect on top and has a big black sunken spot on the bottom. While many will tell you that blossom end rot is a calcium issue, and that is true, it can be caused by heat stress. When stressed, plants can fail to take up enough calcium for fruit production even when it’s available in the soil. 

Other disease issues may also become more prevalent. Think of a stressed plant as a person with a weak immune system. They’ll be more susceptible to disease if they’re already fighting to survive.

How Do I Prevent Heat Stress?

While you can’t change the temperature, you can help your plants in other ways. Here’s how to prevent heat stress in your garden.

Keep Up With Weeding

When it’s hot in the summer, weeding is no one’s favorite task, but it is essential, particularly during these periods. Weeds compete with your plants for moisture and nutrients, putting extra stress on them. 

Mulch

Once your garden is weeded, it’s time to apply mulch. Mulch is a simple way to insulate the soil keeping the soil cool and moist. It’s essential around young, and shallow-rooted plants as the top few inches of soil can heat up quickly.

Water

Especially in times of high heat, water consistently if possible. Watering deeply in the morning is ideal because it allows the water to soak in and not evaporate. However, if you notice dry, stressed plants, water them immediately. Watering the roots either by hand or with soaker hoses or irrigation will save water compared to overhead watering.

Provide Some Shade

Especially with cool-season crops, it can be a good idea to create some shade in the summer heat. You can use tulle or row cover to provide shade. You can also use taller crops like corn, pole beans, or sunflowers to offer a bit of shade to shorter crops. Shading the soil with vining plants like squash and cucumbers keeps the soil cooler for taller crops like sunflowers and corn.

Also, spots in your garden that don’t receive full sun may be an excellent space for summer greens. The morning sun tends to be much gentler than the afternoon sun. 

Don’t Plant, Transplant, or Prune

These activities are stressful for plants and are best done in cooler weather. If you need to transplant, do so in the evening or on an overcast day. You may also want to provide transplants with artificial shade. 

Harvest in Cool Weather

Your produce will stay fresh much longer if you harvest in the early morning or evening. Plus, it will be much easier on you! If you must harvest in hotter parts of the day and are going to harvest greens, bring along a bucket of ice water. Immediately plunging greens into the ice water will help them stay crisp and fresh.

Beating the heat isn’t always easy when you’re a gardener! Thankfully, these tips should allow you to keep your plants healthy through the heat of July and August.

10 Heirlooms Perfect for the Fall Garden

It’s hard to believe it’s already July! If you’re hoping for fall and even early winter harvests from your garden, now is the time to start planning, prepping beds, and starting some seeds. While we love talking about heirloom tomatoes and other summer crops, today we’re sharing ten heirlooms that could make up the backbone of the fall garden.

January King Cabbage

This northern European heirloom dates back to 1897 and is probably one of the only crops you’ll be harvesting mid-winter. They’re slow-growing but super hardy, producing 3 to 5-pound heads in 110 to 160 days. We love their firm heads with light green inner leaves and beautiful semi-savoyed purple-tinged outer leaves. Plant them in early fall for a January or February harvest.

Buy seeds.

Amber Globe (Yellow Globe) Turnip

What’s a fall garden without a few turnips? These heirloom turnips date to 1840 and excel in the cool fall weather. They have sweet, creamy yellow, fine-grained flesh and are best harvested around 3 to 4-inch diameter though they will grow to a 6-inch diameter.

Buy seeds.

Kohlrabi (fall heirlooms)Gigant Winter Kohlrabi

Gigant is another heirloom that’s great for winter storage. It can even stay in the garden in warmer areas all winter, especially if you protect it with mulch. This variety is a Czechoslovakian heirloom that E. M. Meader reselected at UNH. It was introduced in 1989 by SESE and is resistant to root maggots.

This kohlrabi typically grows 8 to 10 inches in diameter but remains tender. It has grown to 62 pounds but is typically between 15 and 20 pounds. It’s delicious used fresh or cooked in any size, small to large. The leaves are also good and can be used like kale.

Buy seeds.

Lutz Green Leaf (Winter Keeper) Beet

Developed before the days of refrigerators, Lutz is a great choice for stocking the larder. These beets are excellent keepers and retain their sweetness and texture even when large (unlike most beets, which become woody when large). Just peel off the skin.

We also enjoyed the tender fall greens in salads. We’ve had problems finding good “true” seed for Lutz Green Leaf, but finally, this is the good stuff – thanks to the fine folks at Uprising Seeds for sharing theirs!

Buy seeds.

Nadmorska Rutabaga

This exciting variety is from seed collected in Lithuania in 2007 by the Seed Ambassadors Project. They’re large, vigorous, and early maturing. They produce green tops and long, oval-shaped roots with sweet golden flesh. They’re great for midsummer planting for a fall harvest.

Buy seeds.

Crawford Bibb (Butterhead) Lettuce

This tasty lettuce is a Texas favorite. It was originally brought to Texas from Oklahoma by the Crawford family. It’s famous for its great flavor, heat resistance, and fast growth. In Texas, it’s normally planted in fall and winter, but we’ve had luck with Crawford during the summer and winter here in Virginia. It’s a favorite of SESE founder Jeff McCormack.

Crawford produces Bibb-type heads with slightly savoyed leaves. It features some red/brown on the leaf edges.

Buy seeds.

Black Spanish Round Fall Radish

This 1846 heirloom is very hardy and an excellent winter keeper. One of my favorite fall radishes, it produces round roots that grow 3 to 4 inches or larger in diameter. The roots have thin black skin and white flesh that’s crisp and pungent.

Buy seeds.

Shallots (fall heirlooms)Grey Griselle Shallot

French gourmet chefs prize grey griselle. It produces these small, teardrop-shaped (1 x 1½ in.) bulbs with hard, grey skin and tender, pinkish-white flesh. They’re ready for harvest in 180 days.

Grey griselle has a distinctive, rich, earthy smell and mild, delicious flavor. Grey shallots are considered by many to be the only “true” shallots.

Buy seeds. Ships in the fall.

Green Glaze Collard

Introduced in 1820 by David Landreth, this unique collard variety produces smooth, bright green leaves. They grow 30 to 34 inches tall and have excellent resistance to cabbage looper and cabbage worm. 

Green glaze is heat- and frost-resistant, slow-bolting, and non-heading. We recommend it, especially for southern and warm coastal states.

Buy seeds.

Oxheart Carrot

These unique-looking carrots date to 1884. They’re a great storage variety that produces thick, sweet “oxheart”-shaped carrots, 5-6 in. long and 3-4 in. wide, weighing up to a pound!

While they require more space than other carrot varieties, oxhearts are particularly suited to rocky or heavy clay soils. The shorter, broader roots tolerate shallow soils that most carrots won’t like.

Buy seeds.

When asked to name our favorite vegetables, many of us will name one of the quintessential veggies of summer. We’ll say summer squash, tomatoes, cucumbers, or sweet corn. The more we garden, the more apparent it becomes that all of these are best in their season. While we may be able to preserve some, it’s also nice to have other crops that are the flavors of fall and winter. These heirlooms provide their unique, homegrown flavors to all of our winter meals. 

Late June Garden Checklist

Here in the Southeast, June is an exciting time in the garden. Depending on your zone, you’ll be harvesting various crops like the last of the spring snap peas and broccoli and the first tomatoes, cucumbers, and squash of the year. It’s also a time where staying on top of the garden chores is critical for continued production into the late summer and fall. This late June garden checklist will help you stay on track and keep your garden healthy and productive. 

June Maintenance

The late June garden to-do list includes some general maintenance tasks to keep your garden growing strong.

Weed, Weed, Weed.

No one loves to spend time weeding, but this time of year is critical. Keep the weeds knocked back to ensure they don’t steal precious water and nutrients from your rapidly growing crops. 

Harvest Regularly

Staying on top of harvesting is essential. You want to pick and use or preserve produce at its peak and encourage continued production. Many crops like cucumbers, summer squash, and green beans will produce more if picked regularly. Allowing the fruit of these crops to fully mature, like you would to save seed, will tell the plant it’s time to die back and stop producing. Check out our previous post, Food Preservation Resources, for information on putting up your harvest.

Add Compost

Heavy feeding crops like corn, tomatoes, and peppers benefit from extra nutrients this year. Sidedressing these crops with good, finished compost can give them a boost to ensure good production. Sidedressing with compost when the plants are flowering is ideal.  

You should also add an inch or two of finished compost to a bed before sowing new successions. This will ensure your soil has enough nutrients to maintain good production.

Stay on Top of Watering

In the Southeast, the temperatures really begin to climb in June. This time of year and further into the summer keeping the soil cool and moist will improve production. A wilting plant is not the only sign of water stress. Deformed cucumbers are often a sign of too little water. Blossom end rot in tomatoes, eggplants, and peppers may also indicate water deficiency, as insufficient water can prevent the plant from taking up enough calcium. 

Remove Old Plants

Remove any plants that are no longer producing, like peas or plants past their prime. You can replace these plants with successions or cover crops, which we’ll discuss below.June garden checklist

Starting the Fall Garden

One of my mistakes as a new gardener was waiting too long to start a fall garden. If you live anywhere with a late first frost date, it can be easy to assume that you have plenty of time to grow crops in the fall. 

Unfortunately, it’s not just the temperature that affects how your garden grows. Dwindling hours of daylight slows crop growth in the late summer and fall.

To know when to sow summer successions and fall crops in your garden, take your first frost date and count backward by the days to maturity for a chosen variety plus an additional 14 days for cool-weather crops and 21 days for frost-tender crops (this accounts for slowed growth). 

For example, if your first frost date is November 15th and you want to grow another succession of Anne Arundel Muskmelons, you should plant your last succession by August 7th at the latest. To get that date, I started on November 15th and counted back 80 days (Anne Arundel’s days to maturity) and then counted back another 21 days to account for decreased daylight.

Late Summer & Fall Crops

Many crops can be planted in June, July, or even later, depending on your USDA zone. Some great options for late summer successions and fall crops include:

  • Snap Beans
  • Summer Squash & Zucchini
  • Cucumbers
  • Cabbages
  • Cauliflower
  • Broccoli
  • Turnips
  • Rutabagas
  • Beets
  • Carrots
  • Greens

When sowing and transplanting this time of year, you’ll want to take extra care to keep plants and seeds cool and moist. Transplant in the evening or on overcast days. Water often and use shade cloth or other plants to keep some afternoon sun off of cool-season crops like lettuce. Place seed trays in a root cellar or fridge to help seeds like cabbage and broccoli germinate in hot weather.

Heat-Tolerant Greens

As spring turns to summer, the last of the cool season greens are being harvested. Any leftover will soon bolt and turn bitter (pollinators love the flowers, though). Thankfully, there are a few ways to continue green production in the hotter parts of the year. 

Here are some great heat-tolerant greens to try:

Using row cover and keeping the soil moist can be especially helpful for lettuce.

Cover Crops

If you have empty beds that you aren’t going to fill with crop successions, it’s an excellent time to start some cover crops. Cover crops suppress weeds, keep the soil moist, and add nutrients and organic matter. Some cover crops you can sow in June include:

  • Buckwheat
  • Sorghum Sudan
  • Cowpeas
  • Soy
  • Millet

Check out these other Summer articles and tips:

Keeping up with summer garden chores is a demanding but rewarding process. Following this June garden checklist and completing these essential maintenance tasks, plus succession and fall planting, will allow you to keep fresh food on your family’s table through late summer and fall.