Harvesting Basil and What High Temperatures Mean for Gardeners

Basil leaves being held in a canning jar.


Yesterday, my thermometer on the south side of my house read 100 degrees. Now, official highest temperature anywhere in Wisconsin was 97 in Waupaca, where the family garden is located. That 100 might be accurate. With the high dew point that's a 117 degree "feels like" temperature. That's about 50 degrees hotter than my preferred temperature of about 65 degrees!

Plants don't feel temperatures the same way we do. The high humidity actually works for plants lessening the amount of moisture a plant gives up to the air. As the skies have been overcast without beating sun, although it is dry, it is not like our plants are experiencing this heat dome as we are. Our plants are growing fast and a little extra moisture will go a long way now. I watered extensively on Friday and Saturday to build up moisture in the soil.

For those of you considering planting fall and winter veggies, with this heat, I would hold off on that plan. Seed germination drops off dramatically at temperatures above 80 degrees for many of these vegetables. If you feel you are loosing too many days, I would water the soil amply the night before and then mulch liberally with a couple inches of finely shredded straw or shredded paper after seeding with a plan to remove it within about 10 days.

This is probably not a good time to transplant or plant perennials or shrubs, but if you must, water well, water foliage to keep transpiration levels low, mulch, and consider trimming back as much top growth as you feel you can.

Lastly, these temperatures have forced me indoors and to play in the kitchen. I thought I would pass these tips along for storing and using basil. Basil is one of my favorite herbs. I plant a lot of it, grown, from seed each year, and almost always run out.

Basil likes it hot. Keep basil flowering tips picked off. When it flowers, the flavor and the texture changes, so keep it picked back. Harvest it down growing tips to about a quarter inch above each joint. When using always discard the stems and any flowers, use just the leaves. Try to pick early in the day if you are storing any quantities, but picking as close to using it is always preferable.

Basil does not like temperatures below 40 degrees. Resist the urge to store basil in your fridge. Temperatures below 40 degrees will brown your basil as if it has been touched by frost. Storing the clean leaves in a container in a dark space maintains moisture content and color for many days with very little wilting.

I have had good results (good color and shelf life), drying basil by placing in an oven on a cookie sheet at 145 degrees for an hour and leaving them in the oven (my oven has a standing pilot and is probably always between 90-110 degrees) for a couple days to finish drying. I then store them in a Mason jar.

Enjoy the heat, if you can. If not, pick basil...