Sowing in the heat:

How to protect your summer sowings.

In the Northeast, we spend most of the spring dodging frosts and keeping germinating seeds cozy indoors. But as the dog days of summer near, the problem becomes just the opposite: how do you encourage seeds to sprout and grow when the sun is so strong? While plants love (and need) warmth and sunlight, they can suffer if the heat is too extreme. Luckily, there are several easy routines and remedies you can use to keep growing all summer long.


Yep, that's right--if your plants are getting too much sun, give them less of it. There are several techniques that can help with this. If possible, choose the shady sections of your garden for planting during this time of year. You can also intercrop shorter plants (like herbs and lettuce) with taller plants (like sunflowers) so they can naturally benefit from their surroundings. Another option is to cover newly-sown seeds and transplanted seedlings with row cover, or create a barrier of shade cloth (however, make sure not to lock in too much moisture which can lead to damping off).


Seeds need a steady supply of moisture in order to germinate, and in hot weather, you may need to water more frequently. Check your seeds twice a day, and if the soil is dry, water. For general watering tips, see this post. The best times of day are the morning and evening; if you water in the heat of the afternoon, most of it will go straight back into the air instead of to the roots of your plants. For transplants, it can be useful to dig your hole a little deeper to create a slight bowl shape that will catch and retain moisture for seedlings.


In summer, not only can you plant seedlings deeper--you can do the same with seeds. Since the surface of the soil heats up and dries out quicker, a few extra layers of soil can keep them moist and safe. Consult the planting instructions on the pack and don't go too much deeper than that--just enough to give the seeds an edge.


During this challenging season, plants can really benefit from having the proper soil. Help your soil do its important work by adding compost or fertilizer. This year, we have partnered with Hudson Soil Co. to offer a high quality compost from property close to our seed farm.

To further improve soil, rotate your crops and try growing a cover crop. Several successions of Buckwheat can be sown throughout the growing season, including the heat of summer (and it looks pretty too).


We've already discussed how morning and evening are the best times to water. Unsurprisingly, those are the best times for you, too. If you need to be out working in the garden, you'll be a lot more at ease if you can beat the heat. Transplant your seedlings in the evening too; that way they'll have the night to rest and adjust before the onslaught of the next day.

While you are out in the garden, keep an eye on out for insect and fungal damage in the garden and assess whether anything needs remedying.


Over-sowing is great insurance if germination rates end up low, but as seedlings grow and compete for moisture, water stress becomes a big issue. Make sure to thin your seedlings to the recommended spacing and remove all but one plant from the cells of starter trays before transplanting. Deadheads Mini Snips are great for thinning without unnecessarily disturbing the soil; but if you prefer pulling your seedlings up, just do so gently.


If your soil isn't retaining moisture well, consider sprinkling a thin layer of straw mulch over your seeds or around your seedlings. The key is not to make the layer too deep--otherwise it could encourage rot and damping off, making it harder for seeds to grow, and create a habitat for pests.

Once your plants are firmly established and looking strong, feel free to add a thicker layer of mulch, but give the stems some breathing room.


As with any season, the choice of what to plant is key. Vining plants like beans and cucumbers can be a good option if trellised since they shade the soil, block weeds, and hold moisture once they’re mature enough. Find trellis netting here. Heat-tolerant crops–like brassicas, corn, and summer squash–will also do well this time of year; however, using the tips above, you'll find you can also grow many seeds you thought were just for spring–like lettuce and spinach.

Follow these summer sowing tips and you're bound to get pretty good germination. Stay cool and keep on sowing!