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Successfully Grow Organic Brassicas

by Dawn
Collection of brassica crops

Best Tips for Growing Cabbage, Kale and Related Crops Organically

Have you ever grown cabbage, cauliflower, broccoli, turnips or rutabagas? How about Brussels sprouts, kohlrabi, kale or collards? Did you know they’re all closely related, and considered brassica or cole crops?

Each crop has slightly different care requirements, so I’ll go through basic care individually, then cover pests and diseases at the end as these are pretty much the same for all. Of course, as before, I’ll add links to some yummy recipes, too.

Introduction to the Cabbage Family

Fun fact: Did you know that all the above crops are the exact same genus and species? Brassica oleracea. What makes a broccoli a broccoli instead of a kale or collard is the variety. For instance, broccoli is Brassica oleracea var. botrytis, while kale and collards are Brassica oleracea var. acephala. Yes, kale and collards are the EXACT SAME PLANT. The only difference is that kale has crinkled leaves and collards have smooth leaves. Cool, huh??

Now, why should you care (assuming you’re not a plant nerd like me)? Two reasons.

First, they share most of the same pests and diseases, which means that you want to rotate these crops each year so you don’t grow any of them in the same soil two years in a row. In fact, a 3 to 4 year rotation is even better, if you can do it.

Second, you’re not going to have a lot of success saving seeds from these crops, unless you’re growing only one of them in any given year. They’re so closely related that they’ll cross breed very, very easily.

In fact, most authorities say you’d have to separate different varieties by upwards of 1/2 mile to keep them from crossing! Most of us don’t have nearly that much room, so unfortunately, this is one crop you’ll probably need to buy, either in seed or plant form, each year.

Welcome to Week Three of Crop of the Week. If you’d like to check out weeks one and two, you can do that here: Growing Peas Successfully and Growing Delicious Organic Beets. If you’d like FREE printable cheat sheets to care for each of these crops, head here to sign up and receive access to my Subscriber’s Resource Library. No spam, I promise, just lots of free information and a weekly newsletter.

Growing Broccoli

broccoli plants


Believe it or not, broccoli wasn’t brought to the U.S. until after World War I! Obviously, it has become very popular since then.

Seed Starting

You’ll want to start your broccoli from seed 6 to 8 weeks before your last frost. Here in Zone 6b, I consider last frost May 15, although most charts give a somewhat earlier date. March 15-22 is about right for starting broccoli seeds here, as far as I’m concerned.

There are no real particulars on starting them indoors, you’ll just care for them as you would other indoor seedlings. If you need some help with seed starting, I have two posts that might be of interest: Five Essentials for Indoor Seed Starting and Eight Steps to Successful Seed Starting.

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Planting Out

As with all seedlings, be sure to acclimate them to the outdoors before planting. You’ll want to plant your seedlings out once they’re 5 to 7 inches tall and it’s about 4 weeks before your last frost date. Broccoli likes rich soil, so adding some compost before planting is a good idea.

When you plant, set them 1 to 2 inches deeper in the garden than they were in the pots and 1 to 2 feet apart. Your rows should be 2 to 3 feet apart. Don’t crowd your plants as they won’t grow nice big heads if you do.

NOTE: Broccoli can handle light frosts, but if you’re expecting a hard freeze, be sure to cover your plants with a sheet, cloche or blanket for protection. DO NOT use plastic as this will transmit the cold to the plants and kill them.

Feeding, Watering and Mulch

Broccoli requires a bit more water than some crops, so be sure it receives 1 to 1 1/2″ a week. Otherwise, flavor will suffer.

When your plants have been growing for about 2 weeks, give them a top dressing with compost tea, and repeat this monthly until a week before you’re going to harvest.

Be sure to mulch your broccoli generously to keep the roots cool and retain moisture.


Cut just below the heads with a sharp knife before the flowers within the heads start to open. When you do this, you may find that your plant will produce some smaller side heads. These are also good to eat and will give you a secondary harvest.

Growing Cabbage



According to the Heirloom Life Gardener book, Roman soldiers used cabbage leaves to bandage their wounds, as cabbage contains glutamine, an anti-inflammatory. Just a little trivia tidbit for your next cocktail party. You’re welcome!

Seed Starting

Cabbage seeds should be started even earlier than broccoli, 8 to 12 weeks before your last frost. Again, if you missed it this year (as I did), you can purchase plants from your local nursery, and worry about starting from seed another time.

Planting Out

When your cabbage seedlings have 4 to 6 true leaves and days are consistently around 50F, it’s time to plant them outside. Again, be sure to acclimate them and give them nice, rich soil in full sun. You should plant them 12 to 18 inches apart in rows 2 to 3 feet apart to allow them to grow and develop nicely.

Care in the Garden

As with all cool season crops, a nice thick layer of mulch will be much appreciated. Hand weeding is best so as not to damage delicate roots.

You should also plan to side dress your cabbage with compost about 3 weeks after planting.

Pro tip: To be fair, I had never heard this before, but read it in several places when doing research for this post. Once your plants have formed heads, if there is a very heavy rain, the head can split (maybe you’ve experienced something similar with tomatoes).

Unlike tomatoes, however, there’s something you can do with cabbage. Immediately after the rain ends, grasp the entire head in your hands and twist it 1/4 turn (90 degrees). This will break some of the roots and slow the growth of the cabbage, keeping it from splitting, at least in theory. I’ve never tried this particular operation, so if you have, please let me know how it went, I’d love to find out!


Much as you would with broccoli, cut below the head with a sharp knife.

Growing Kale and Collard Greens

kale plants


Kale is actually an ancient crop, and was known as early as the fifth century BC. In Colonial America, it was known as colewort. Hmmmmm….I’m guessing if that name had stuck, kale might not be as popular as it is today.

Seed Starting

Kale and collards should be started indoors about 8 to 10 weeks before your last frost.

Planting Out and Care in the Garden

Kale and collards are extremely cold-hardy plants. They also grow quite quickly, so once your seedlings are getting too large to keep indoors, feel free to plant them outside.

Be sure to plant them at least 12 to 18 inches apart in your garden, as they become quite large and you don’t want them too crowded. Again, as with all vegetables in this family, they prefer rich, moist soil, so amendment with compost before planting would be appreciated, as would a thick layer of mulch once the plants have begun growing well.

You may have noticed decorative kale sold in garden centers in the fall. The edible varieties aren’t any different, and many will continue to produce all the way through December, even in the colder areas of the country. These would, of course, be from a late summer planting, as your spring-planted kale won’t survive hot summer temperatures.


Feel free to harvest kale and collard greens repeatedly. Don’t cut the entire plant, just take some leaves off, and you’ll have a more or less continuous harvest for quite some time.

Growing Kohlrabi

Funny-looking, aren’t they?

Ahhhhh, my favorite member of the cabbage family! Have you ever eaten kohlrabi? I know many people haven’t, and maybe you’ve never even seen a kohlrabi. You need to try them, though, they’re so yummy!

I have a vivid memory of being in my grandmother’s garden as a kid and her handing me a kohlrabi to try. I was suspicious, I must admit. I mean, they’re kinda strange-looking, but I ended up really liking it.

As with other cabbage family crops (other than broccoli and cauliflower), I prefer my kohlrabi raw. It’s crunchy and sweet, much milder in flavor than many of its relatives.

Care in the Garden

Kohlrabi is best sown directly into the garden 4 to 6 weeks before the last spring frost. You can start by planting 10 seeds to a foot. Once the seedlings are 4 inches tall, thin them to 5 inches apart.

As with all cabbage relatives, a nice layer of mulch and hand weeding will make your plants happy. Kohlrabi also appreciate an occasional drink of compost tea.

The really nice thing about kohlrabi is that it doesn’t mind the heat as much as some of the others. You can actually plant it every few weeks all summer (except in very hot weather areas) until 6 weeks before the first fall frost (but let’s not think about fall yet, ‘k?)

If you haven’t grown any members of the cabbage family before, I would humbly suggest that you start with kohlrabi. Although brassicas tend to have lots of trouble with pests, I had no trouble when I grew my kohlrabi and the small size of the heads (you want to harvest when they’re no more than 2 inches in diameter) means that you can easily find any critters that might be hanging out on your harvest.

Pests and Diseases

<<Sigh>> Ok, now we have to talk about the yucky stuff. Unfortunately, brassicas are REALLY attractive to an alarming array of pests. Diseases aren’t quite as much of a problem, but I’ll mention a couple, just in case.

In all honesty, the best way to keep pests off your cabbage family crops is to grow them under row covers. Really, it’s the only way you’re going to keep them even remotely pest-free. Being that cabbage maggots, aphids, cabbageworms, slugs, cabbage loopers, cutworms and Harlequin bugs all love brassicas, I STRONGLY suggest row covers. You can find a nice selection here, and probably a more limited selection at your local garden center.

If you’d like more detailed information about row covers, check out this link.

You can try controls like hand picking or insecticidal soap, especially for Harlequin bugs, which are easy to see, but I really recommend row covers to save yourself a lot of aggravation.

Although cabbage family crops can have problems with black leg (fungus), club root, black rot and fusarium wilt, good crop rotation practices and healthy, well-nourished plants will go a long way towards keeping these at bay. Many varieties are also available that are resistant to these diseases. I’d suggest checking out Baker Creek Seeds when looking for seeds.

Helpful tip: Even with careful pest control, it’s still possible (probable?) that a few worms will find their way into your crops, especially your broccoli. If you’d rather not have any supplemental protein with your dinner (ewwww!!!!), soak your broccoli (or any of these crops) in warm water and a little bit of vinegar for 15 minutes before cooking.

I would venture to say that soaking cabbage or broccoli you’re going to eat raw might not be a bad idea either, just be sure to rinse it well to remove the vinegar before eating.


And now for the fun stuff! I found a bunch of yummy recipes for you!

  • Bon Appetit Brassica Recipes– Seriously, 25 recipes that made my mouth water (I mean, shaved kohlrabi with apple and hazelnuts? YUM!)
  • Food52 Recipes- Another 19 yummy-sounding recipes (and I’m pretty sure I’ve got to make the Bubble & Squeak just because it’s called Bubble & Squeak!!!)
  • In this BBC Food Collection, you can just click the particular crop you want recipes for and you’ll get a whole collection for each.
  • The pictures in this Gourmet Traveler recipe collection will make you drool!

You may have noticed you didn’t see anything today on Brussels sprouts, turnips, rutabagas or cauliflower. This is because they do best as a fall crop. Don’t worry, though, I’ll be doing posts later in the summer (probably around the end of June) on fall crops, so you’ll get all the info then!

I hope you’ve enjoyed my post and learned a whole lot about growing brassicas. Don’t forget, a concise cheat sheet of everything covered in this post (minus the recipes) is available in the Subscriber’s Resource Library today. Just click on this link to see what’s in store for you and to sign up.

Posts Related to Growing Brassica Family Crops

As always, I welcome comments and questions, and if you have an appropriate Pinterest board, the pictures below are pinnable so you can save them for later. Thanks for reading, smile and have a crazy organic day!

assorted brassicas
assorted kale plants

Best Tips for Growing Cabbage, Kale and Related Crops Organically


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Sarita 03/30/2019 - 6:37 pm

So much good information here again, Dawn. These “brassicas” grow really well up here (we’re in Zone 2a), especially the kale. Last year our broccoli just didn’t take for some reason – think maybe I got it planted too late. Can’t wait to get started this year though!

Dawn 03/30/2019 - 6:39 pm

Zone 2a, wow! I can’t even imagine having such a short growing season. I think I’d go nuts. I would imagine any of these would work well for you though, as they really don’t like hot weather.

Nikki L Gwin 03/29/2019 - 5:56 pm

What a very thorough and detailed post! Great job. I have trouble with those cool crops because we don’t get much “cool” here in Alabama. Doesn’t stop me from trying… although, I never get it planted early enough.
🙂 gwingal

Dawn 03/29/2019 - 7:02 pm

Some of them can be planted in the fall for an early spring crop. Is it warm enough where you are to give that a try?? You might need to protect them with row covers if you get a cold snap, but wondering if that might be a better idea for you.

Linda Carlson 03/29/2019 - 12:32 pm

Love it.. lots of good information here.. I have not had good luck with broccoli or cauliflower but do well with turnips and ok with cabbage

Dawn 03/29/2019 - 4:21 pm

I haven’t really tried them yet because I don’t have a good system for row covers yet, but hoping to change that before late summer (as I’m going to try these crops for fall).


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