Grow the Best Brassicas This Fall!

Grow the Best Brassicas This Fall!

An article by Travis Key from Lazy Dog Farm

In the backyard garden, big plants don’t always result in big harvests. You could have big corn plants with tiny ears because the corn wasn’t pollinated sufficiently. You could also have a huge tomato plant that looks great but produces few tomatoes due to an overload of nitrogen in the soil. However, in the case of many cool-season veggies that we grow in the fall garden, big plants do equal big harvests.

It is especially the case with plants in the Brassica family. This would include delicious backyard garden veggies like broccoli, cauliflower, cabbage, Brussels sprouts, and more. With these veggies, the size of the plant is usually directly correlated with the end harvest.

And most of these vegetables are harvested only once. When you cut a head of cabbage, the remaining few leaves don’t grow another head of cabbage. When you cut the main head of broccoli or cauliflower, that’s the major harvest. You will get a little side shoot production if you leave the plant in the ground, but it’s usually not that significant. Same thing with Brussels sprouts — once you cut that stalk and harvest the sprouts, it’s done.

This means that you must be on top of your game as far as feeding these plants early. If your broccoli plants start producing broccoli and the plants are small, there’s not much you can do at that point. It’s not like a pepper plant where you can fertilize, revive the plant, and get some good late season production from it.

Start Feeding Early

We start feeding our brassicas when they are tiny little seedlings in a seed tray inside our greenhouse. Once the seedlings have their second set of leaves (also known as “true leaves”), we’ll start feeding them a low dose of AgroThrive General Purpose at least 3-4 times a week. In situations where we’re wanting our transplants to be ready for the ground faster, we’ll increase our feeding frequency to daily — fertilizing them each time we water.

We’ll usually mix 1 ounce of AgroThrive General Purpose per gallon water and use our Siphon Mixer to inject it through our watering wand. This makes it easy to fertilize and water at the same time. We’ve found that these frequent, low dose applications of AgroThrive promote an excellent root system in our seedlings and allow them to hit the ground running when they’re transplanted.

As mentioned above, you can adjust your feeding frequency based on your intended in-ground planting date. If it looks like fall is going to come early, you can push the plants and have them ready to transplant sooner. If it looks like summer is going to be extended, you can dial back the number of fertilizations per week. This will keep your transplants from getting too big in your seed starting trays and getting root bound.

Keep It Up!

Once you put your brassica transplants in the ground, you’ll want to continue feeding them to get big plants and big harvests. If your soil fertility is questionable, it’s not a bad idea to use AgroThrive General Purpose as a soil drench prior to planting. Mix 1-2 ounces per gallon of water and pour onto the soil where you’ll be putting your transplants. This will help activate the soil biology and provide some initial nutrients for the brassica transplants.

Once the brassica plants overcome their transplant shock and start growing, we like to feed them at least every 2 weeks with AgroThrive General Purpose. For smaller plantings in our raised beds, we’ll simply mix 2 ounces per gallon of water in a 5-gallon bucket and pour alongside the plants in the bed. For larger plantings in our in-ground garden, we’ll inject it through our drip irrigation system. Either way, this frequent feeding (also called “spoon feeding”) ensures you’ll get the size you need on those cool season plants.

From our experience, cabbage and Brussels sprouts will tend to be a little hungrier than broccoli or cauliflower. They’ll all benefit from frequent fertilizations, but it will make the biggest difference on your cabbage and Brussels sprout plants. A broccoli or cauliflower head is only going to get so big, but a cabbage head can get huge if you feed it right. Brussels sprouts will also tend to make taller stalks and have more uniform sprout development when fed properly.


Thousands of gardeners have been tuning in to The Lazy Dog Farm YouTube channel where Travis covers a variety topics ranging from how to successfully start seedlings to how to make a flavorful hotsauce that packs a punch. Accompanied by his wife Brooklyn and their two boys, the gardens on their 2 acre homestead in southwest Georgia are always filled with a wide variety of vegetables that are enjoyed fresh or preserved for later.

1 comment

  • Jerry Jackson

    What type of siphon does Travis use? Thank you.

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