If this is edible kale, it’s a sign that the plant is bolting. If you have not already, harvest any leaves that you want and save or cook them. Pulling the flowers is not likely to halt the bolting process—a sign that it is too warm for the plant to produce leaves. You can cut the flowers for a vase or leave them for appearance, but as an annual, the plant is almost done.

For a second crop this year, set out new plants in the late summer/fall. Kale like cool weather.

You can harvest the leaves as long as the taste is appealing. After the plant bolts (sends up flowers) the leaves may become bitter.

Kale can take a light frost. In fact, kale is best in the fall after exposed to a few light frosts. However, it won’t survive freezes outside so it’s best to pick the leaves. You can always blanch and freeze to store over the winter. Plant new seeds in the spring.

Kale usually takes about 65 to 80 days from seed to harvest, but that depends on variety, conditions, etc. Plants sometimes slow their growth if they are stressed, such as temperatures too hot or cold, not enough water, pests or diseases, or crowded roots (for container-grown). Make sure your plants have enough room in their pots, and that they are getting the right amount of light, water, and nutrients. It sounds like you can start harvesting the outer leaves now for cooking, but allow the inner ones to keep growing (sometimes people harvest a few baby leaves for salad, but be careful not to pick the growing innermost section). Depending on your climate, they can produce for several months, and over winter in Zones 7 to 9. If you live in a cold climate, you’ll need to provide winter protection to extend the season.

A lot. Seriously though, some of the seeds that you plant may not come up, other seedlings/plants may be subject to disease/insects or weather or cultural conditions that would either reduce their productivity or kill them. Also, it would depend on whether you harvested the whole plant, bunches, or individual leaves, and how those leaves were harvested (if you harvest the lower leaves, it will produce more leaves up top). However, basic average yield in a home garden for a 10-foot row, at 8- to 12-inch spacing, is about 4 to 8 pounds. Sources recommend about 4 to 5 plants per person. Hope this helps!

According to one chart produced by a Georgia county extension, Feb 1 to March 10 is good for a spring sowing of kale seeds or transplants in middle Georgia. Northern areas, such as Atlanta, should add 2 to 3 weeks to those dates (start around Feb 14). You might call your county’s Cooperative Extension for specific dates for your area. Contact information can be found at: 

http://www.almanac.com/content/cooperative-extension-services

Kale is usually treated as an annual, even though it is biennial. When treated as an annual, you can pull up the old stalks and roots, then grow new plants next growing season.

However, depending on your climate, the variety you choose, and how well protected it is over winter, your kale might make it through winter to produce a small harvest in spring before it goes to seed. If you wish to try this, and you live in a cold climate, then cut down any vegetation that has browned and died back, then provide a thick mulch, such as straw, over the kale bed in fall after harvest is over. In spring, uncover the plants when signs of growth emerge.

If they are leaf buds, leave them be. If they are flower buds, then the plant is starting to bolt (form a flower stalk), which can make the leaves taste bitter. When you see a flower stalk forming, snip it off as soon as possible, to delay the flowering process. (The flowers are edible.) It is a sign that you should harvest the leaves as soon as possible before the flavor becomes too bitter.

Kale is a biennial–setting leaves the first year, and flowering the second year before dying. However, in certain cases, kale can bolt the first year if they are under stress, such as high heat at certain stages, or dry soil.