Most gardeners would know by now that almost anything can be grown in a pot and cabbages are no exception. But before we go into the ins and outs of how to grow cabbage in pots or containers on your balcony, patio or deck, you have to understand that cabbage plants can get quite large. Take a look at this photo of a cabbage plant in one of my garden beds.
Yes, that’s just one plant, although you can see a few smaller ones around it. Don’t mind all the small holes in the leaves – I’ve been picking off green caterpillars or cabbage worms daily! Thankfully, I don’t have to also deal with cabbage loopers. Although I do have a pop-up crop cover over this garden bed, I have been keeping the front partly open because I also have squash plants in there which need pollinating.
This plant came from seeds I set down some time ago and forgot about. When I found them again in early spring, there were only around four spindly seedlings which I didn’t hold out much hope for.
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Nevertheless, I decided to plant them in this garden bed to see what would happen. Anyway, it’s taken around four months for that particular plant to reach that size. That’s another thing to be aware of when growing cabbages – they can take quite a long time to grow. But, I am hoping for a nice head on this one eventually. So, let’s get into everything you need to grow if you want to grow cabbages that form nice cabbage heads in containers.
Your Choice Of Container Is Important
As you can see by the size of this one plant, you’re going to need a large container if you want to grow these beauties in pots. This particular plant measures 56 cm (22 inches) wide and 71 cm (28 inches) high. So, to ensure your plant has enough room to grow, you’ll need a pot that’s at least 50 cm (20 inches) in diameter with a depth of around 50 cm (20 inches) deep. Grow bags, like those used for potatoes, would also work well. Just make sure your container has plenty of drainage holes so that excess water can drain away freely.
From what I know about growing brassicas in general, they have a fairly extensive root system and the height of the plant itself will usually signify how far the roots have gone down into the ground. In saying that though, when growing anything with deep roots in containers, you’ll often find that the top growth won’t get quite as large due to the restrictions placed on the roots.
This means that you can probably only grow one cabbage in a single pot. However, if you do plant two or three together, they should still grow but you’ll end up with smaller heads. Better still, instead of growing popular green cabbage varieties like savoy cabbage, napa cabbage, Chinese cabbage or large red cabbage types, opt for one of the mini cabbage varieties that are now available like ‘Tiara’, ‘Miniball’, ‘Red Mini’ or ‘Gonzales’. These are all hybrids and have been bred for gardeners who only have a small space.
Here’s A Healthy Cabbage In A Large Terracotta Pot
Use The Best Potting Soil You Can Afford
You’ll find that cabbages are heavy feeders, so you’ll want to start off right by using a really high-quality potting mix. Or, you can do what I do and mix good quality potting mix with homemade compost containing lots of organic matter at a ratio of 1:1. This will save you a little money because the compost you’ve made hasn’t cost you anything. Especially if you’ve followed my easy guide on how to make your own compost.
Generally, it’s a good idea to start your seeds off in a small tray that you’ve filled with coco coir and perlite. You can even start these indoors if your area gets frost over winter. But don’t make the mistake that I made with my cabbage seeds and that is to not give them enough light or you’ll end up with long lanky seedlings. Either put your seedling tray on a very bright windowsill or invest in a grow light, like this quality natural light solution from GE. This brings us to where you should position your cabbage plants once you’re ready to transfer them to their pots.
Full Sun And Plenty Of Water Is Essential
Your cabbage plants will appreciate as much sun as you can possibly give them. Even though they’re regarded as a cool season vegetable, they still need at least 6 hours of direct sunlight daily. This is where growing in containers is quite useful. It means you can move your plants around during the day wherever you can find a sunny spot.
You also want to ensure that you give your plants plenty of water. Aim for moist soil at all times. Remember that pots do dry out much quicker. This means you might need to water your plants every two or three days during warmer weather and at least once a week during the cooler months.
Make sure you check the soil moisture often so that your plants don’t dry out. Remember that these plants really don’t mind the cold weather all that much. In fact, they can even benefit from a little bit of light frost. However, if you’re expecting heavy frosts before your fall harvest, you might need to invest in some type of row cover material. This should protect the entire plant during these icy spells.
Don’t Forget To Feed Your Cabbages
Although you’ve started your plants off right by adding some nice rich compost to the potting mix, you’ll still need to feed them during their long growing season. My favourite way to keep my cabbage seedlings and other young plants and veggies fed is to use a liquid feed based on seaweed and fish emulsion. My go-to liquid feed at present is Maxicrop which has an N-P-K ratio of around 5-2-4. I mix this up in a 9-litre watering can with a rose attachment. I add around 25ml of the fertiliser to the full nine litres of water.
Alternatively, you could choose to use compost tea or other organic fertilizers to keep your plants nourished. I find this solution works really well for all my crops including leafy vegetables and fruiting ones. Ideally, you want to water your cabbages with liquid feed around once a fortnight.
Pests To Look Out For
As you can see from the photo of my cabbage plants, your biggest problem will be protecting your plants from those pesky green caterpillars. If you notice those small white butterflies around your garden, then this is a problem you’ll face because the caterpillars are the larvae of these pests.
Although I’m not overly concerned about the holes in the outer leaves, I don’t want the larvae getting anywhere near the heads of the plants because this is going to spoil my harvest. The best way to keep your plants safe from these pests is to use insect covers. You can actually now find crop covers in a range of sizes so there should be one available that will fit over your pot or container.
It’s totally fine to cover your cabbages with one of these early on. These plants don’t need to be pollinated. Apart from constantly picking off the caterpillars when you see them, this is the most environmentally friendly way to protect your plants. As a last resort, you can use something like Derris dust to sprinkle over the plants as this should kill any caterpillars already present.
One of the other problems you might face is aphids. These tiny sap suckers love the tender new growth. They can be easily removed with a strong jet of water or by spraying your plants with neem or white oil. Depending on where you live and garden, you might also have a problem with flea beetles. These can also be controlled with neem oil or an organic pesticide. As a home gardener and especially if you’re growing in containers, you shouldn’t have any problems with black rot which is a bacterial disease horticultural growers have to be mindful of.
Frequently Asked Questions
Once your cabbage plant has formed a nice round head that feels firm, you’ll know it’s ready to be harvested. Just cut off the head at the base with a sharp knife.
If you’ve chosen a large pot and some of the mini cabbage varieties to grow, there’s no reason why you can’t grow something else in the same pot. Root crops like carrots and onions make good companions as do herbs like mint and thyme.
Yes, this is possible as long as you have a grow light. This will ensure your plants get the required amount of light on a daily basis.
Cabbage growers need to be fairly patient. These plants can take quite a while to grow, depending on the variety. The time to maturity should be shown on the seed packet, so use this as your guide.
Although they’re regarded as a cool-season crop, cabbages will grow all year round if they’re given the right conditions. If you want to grow them indoors over winter, you just need to put them under a grow light.
Final Thoughts
As long as you’re patient and use the right container, cabbages aren’t at all difficult to grow in pots. You just need to provide them with enough sunlight, water and fertiliser. If you do this, you can be harvesting a nice crisp head in just a few month’s time.
Just remember to keep an eye out for those white cabbage butterflies and their hungry green caterpillars. Using a crop cover to protect your plants will probably help if you keep the opening zipped up.
As a final note, it’s been about a week since I started this article (I’ve been busy with my freelance work). The cabbage head is now starting to form nicely. Here’s a photo.
Hopefully, it won’t take too long to get to a reasonable size and will be undamaged and free from bugs! A late summer or early fall crop of cabbage will be great and all those excess leaves will be great for the compost.
