Bolting Basics

By Kymisha Montgomery, CGC Urban Agriculture Coordinator

Now that the temperatures are in the 80s consistently all week, it’s a good idea to keep an eye on our beloved brassicas. But did you know that brassicas aren’t the only family that has the potential to bolt in warmer temperatures?

Besides broccoli, Brussels sprouts, collards, cabbage, cauliflower, bok choi and kale—which are in the Brassicaceae or mustard family—carrots, celeriac, celery, parsley and parsnips in the Apiaceae or umbellifer family also have the potential to bolt. You can say the same for onions, shallots, leeks and garlic in the Allium family as well as chicory, endive, artichoke, lettuce and radicchio in the Asters family.

Bolting is caused by a combination of complex interactions between temperature, day length and stresses of various kinds. When stress goes on long enough, plants switch their energy to survival mode, forming flowers for reproduction. This is known as bolting.

How can bolting be prevented? Here are a handful of things you can do in your garden.

Plan Ahead

Planning your garden in preparation for the switch from cool to warmer weather can help decrease some of the stress on your plants. Try including techniques like companion planting. Using natural shade from crops that will get taller, like corn or flowers, can help provide shade to more sensitive plants during days of warmer temperatures. 

Provide Cover 

As summer approaches, day length increases, which can cause unwanted stress on your crops. If you couldn’t plant your spring crops in a shaded area of your garden, using a row cover or shade cloth can help decrease some of those high temperatures that are unwanted by cool weather crops.

Choose Varieties with Bolting in Mind

Here in Cincinnati, we typically have a pretty quick transition from cool to warm or even hot days. Choosing bolt-resistant or long-standing varieties can help decrease the time they are exposed to the unwanted high temperatures. You can also choose faster-maturing varieties of your favorite cool weather crops to get the harvest in before the heat!

Use Mulch & Water

Adding straw or another organic mulch material around your cool weather crops and watering regularly can help keep the soil temperatures cool.

Pinch Off Flowers

Pinching off any flowers when they appear may be able to extend your harvest by a few weeks. Fingers crossed!