How to Keep Herbs from Bolting

(Delayed bolting means a larger harvest of tasty leaves.

One bane of fast growing herbs is that they bolt quickly when the weather starts to warm up. Bolting is the process of rapid growth (sometimes looking leggy and spindly). Plants quickly flower and set seeds. When most plants enter this phase, they stop producing leaves. To encourage your plants to keep leafing, as opposed to flowering, these tips will help:

How to Keep Plants from Bolting

These tips should be applied with care. Some call for snipping new growth from plants, which can cause plant shock if you do it too aggressively. Likewise, if a plant is already stressed, under bacterial or insect attack, or looking unhappy, being rough with it is probably not a good idea until you address other, more pressing, concerns.

Keep plants in a cooler or slightly shadier location. This should keep the temperature lower for a bit longer and slow the plant's development.

Put plants out in the garden a little earlier in spring so you can to extend the cool growing season for them. The plants will still bolt when the weather gets hot, but you'll have more time in cooler weather for abundant leaf growth.

Pinch back flowers further down the stem than you probably have been doing - about 1-1/2 to 2 inches. Pinching back at the base of the flower usually works, but going further down the stem can sometimes buy you more time before the flowering process starts all over again.

Dense leaf growth on mature dill stems

Start harvesting leaves while the plant is still immature. The more leaves you harvest, the more energy the plant will expend on leafing out rather than on flower production. This really well works for a while, but nothing works forever. Take only a quarter to a third of the stem at a time.

Harvest the plant through the growing season. Do this three or four times from spring to fall (or whatever your season happens to be).

Some good herb candidates for this type of approach are: basil, cilantro and dill.

Staggered Planting

Since bolting is inevitable, try staggering your plantings, too.  You can start seeds indoors in batches every few weeks, and put them out as they develop to the seedling stage.  Since intense summer sunlight can be brutal to young plants, introduce late additions to the outdoors in gentle stages -- say every morning for a week to 10 days.  When they're acclimated, place plants in a partly shady spot if you live in a high heat area. A good option is under or behind another plant that screens the light somewhat. Adding a protective layer of mulch is also a good idea.

References

Photo 1 Cilantro1.jpg Courtesy of Jeffrey Collingwood StockXchng,com  -  http://www.sxc.hu/profile/Spiders

Photo 2 Flowering Dill Courtesy of Morguefile.com