Kohlrabi is one of those vegetables that looks weird but tastes pretty good. It was time for me to try growing some in my container garden. But the question was are they easy to grow in a pot?
You can grow kohlrabi in pots but it has to be at least 16 inches deep and wide. The plant needs the right temperature between 40 to 75 degrees Fahrenheit to grow well. You need to use the right potting soil and harvest the kohlrabi when they are 3-4 inches in diameter.
There’s a lot more that goes into growing kohlrabi in pots and I’ve written a detailed guide that you will find useful below.
Pick a suitable variety for growing in pots
You can grow most varieties of the kohlrabi in pots because you will harvest them when the base is about 3-4 inches in diameter. You can get kohlrabi plants that grow white, green, or purple in color.
I’ve listed some popular varieties of kohlrabi that you should be able to find. You can get the seeds at a local garden center or an online store.
|Purple Vienna||12-18 inches||55-60 days|
|Early White Vienna||6-8 inches||55 days|
|Konan Hybrid||12-18 inches||40-45 days|
|Sweet Vienna||9-15 inches||45 days|
|Quickstar||6-8 inches||37 days|
Choose the best time to grow kohlrabi
Kohlrabi is a plant that prefers the cool-season when the temperature is between 40 to 74 degrees Fahrenheit.
If the temperature goes beyond this point, the seeds won’t germinate. And the plant will start to bolt where it’s trying to produce seeds. The kohlrabi will become woody and bitter.
The best time to start growing kohlrabi is a few weeks before the last frost date in spring. Or a few weeks before the first frost hits your area in fall.
Understand how long it takes to grow
The time your kohlrabi plant will take to grow depends on the variety. You can find them ready for harvest in 45 to 60 days after sowing seeds.
You should check the seed packet to get the exact timeline on when your kohlrabi will be ready for harvest.
The best time to harvest the base is when the size is about 3-4 inches in diameter. If they grow too large, the base will become woody and bitter.
Choose the right pot to grow kohlrabi
The kohlrabi plant has deep roots and that’s why many people think it’s difficult to grow them in a container. You just need to pick a pot that is at least 16 inches deep and wide and it will grow well.
Pick a pot that has drainage holes at the bottom. This helps drain out the excess water and protect the plant from getting excess water. The problem of overwatering is quite common that causes problems like root rot.
You can choose any pot made from materials like ceramic, terracotta, plastic, metal or wood. I prefer plastic because it’s inexpensive, lightweight, and durable.
And it does not lose moisture as fast as some other options like terracotta. This means I don’t need to water the plant as often.
Prepare the pot for planting
Once you have selected the pot to grow kohlrabi, you need to prepare it for the potting soil and plant. You may have bought a new pot or reusing an old one. But you need to sterilize it before use.
You can soak the pot in a solution containing 1 part bleach and 10 parts water. Keep it in this solution for an hour and rinse it with clean water. Then dry the pot under the sun.
This process of sterilization helps remove any unwanted pests, diseases, and chemicals that could be present in the pot and harmful to the kohlrabi plant.
Keep the pot in a suitable location of your container garden. You don’t want to have to move the pot after you have added the potting soil as it will get heavy.
When you’re adding soil to the pot, make sure it’s sterile potting soil rather than soil from your garden. Because the garden soil may contain too much sand or clay that is not suitable for growing kohlrabi.
It may also contain pests, diseases, and chemicals that could harm the plant. The only situation you could use garden soil is if you have an outdoor garden containing rich and fertile soil.
You can either buy the potting soil from a garden center, nursery, or online. Or you can make some of your own using a mix of 1 part perlite, 1 part vermiculite, and 1 part peat moss. If you have compost, add some of that to enrich the potting soil.
I like to use compost because it adds good texture as well as nutrients and beneficial microorganisms to the potting soil.
Before you can add the potting soil, place a layer of newspaper at the bottom of the pot. This will prevent the potting soil from falling out of the drainage holes.
Add the potting soil till it fills the pot and only 1-2 inches remain from the top. Keep this space empty so you can water the potting soil without it spilling out.
Plant the kohlrabi seeds in the pot
The kohlrabi plant has deep roots so I would suggest planting them in the pot rather than starting seeds indoors and then transplanting.
If you transplant, there’s a higher chance that the roots get damaged or the plant gets stressed and growth is stunted. So, only start seeds indoors if you really have no choice.
I would suggest growing one plant per pot so there’s enough space for it to spread it’s roots as well as branches. You would face the problem that the plants are competing with each other for nutrients.
Push the kohlrabi seed 1/2 inch into the potting soil and keep it moist with regular watering. Be careful when you water the potting soil so that you don’t displace the seeds. Make sure the potting soil gets sufficient sunlight and water and the seeds will germinate after 3-10 days.
Give the plants the required sunlight
It’s best to keep the pot in a location that gets at least 6-8 hours of direct sunlight every day. Kohlrabi does need a lot of sunlight to grow in the required time.
You should be careful that the plant does not get too hot especially in the afternoon. You may need to move the pot to a shaded location during this time.
Water the kohlrabi plants well
You need to keep the potting soil moist for the kohlrabi to grow well. But be careful that you don’t overwater it. If the plant gets too little water, the growth will be stunted. And if there is too much water in the potting soil, you risk root rot.
I like to check up on my plants every morning for things like moisture, pests, and diseases. Just stick your finger 1-2 inches in the potting soil to feel the moisture.
If it feels dry, you need to water the potting soil deeply. This means using a watering can to keep pouring water till it runs out from the drainage holes at the bottom.
If you have enough drainage holes in the container, the excess water will flow out from the bottom and avoid the problem of water staying in the container.
I prefer the morning time because you can water the potting soil well and any excess moisture on the plant will evaporate as the sun comes out. This helps prevent a humid environment on the plant that can cause fungal diseases.
You can also add a layer of organic mulch such as dried leaves, wood chips, or grass clippings on the potting soil. This helps the potting soil retain moisture longer as the mulch insulates it.
Thin the unwanted kohlrabi seedlings
When you plant the kohlrabi seeds in the potting soil, make sure to put in 2-3 seeds at once. This improves the chances that at least one of them will germinate.
It may happen that more than one seeds germinate but let them grow till the seedlings are 2-4 inches tall. You can then use the process of thinning.
You need to cut off the unwanted seedlings and let one remain in the pot. Pick the one that appears healthiest and let it continue to grow. Use a scissor or pruner to cut the remaining ones. You can add them to the compost pile if you have one or use them as microgreens in your salad.
You want to only grow one seedling per spot in the pot so there is no competition for nutrients and resources. This helps the single kohlrabi plant to grow the best it can.
Provide good fertilizer to the kohlrabi plants
The best fertilizer you can use for your kohlrabi plants is adding compost to the potting soil. You can add this when you’re preparing the pot with the soil. You can also keep adding a layer of compost on the potting soil every month while the plant is growing.
The compost will provide beneficial nutrients and microorganisms to the potting soil. If you don’t have compost, you can consider adding organic fertilizer instead. You can use a balanced fertilizer that has an N-P-K value of 5-5-5 or 10-10-10.
If you’re using a granular fertilizer, you can mix it in with the potting soil while preparing the container. And also add it to the potting soil every month.
If you’re using liquid fertilizer, you can spray it on the soil and foliage every couple of weeks. Or you could dilute it with a lot of water and use it for watering your kohlrabi plants every day.
Make sure to follow the manufacturer’s instructions when using fertilizer. It will show you how much and how often you need to use the fertilizer.
Prune the kohlrabi plant
Pruning is a process where you cut off leaves and branches of the plant so that it can grow better. The first candidates to cut off are the foliage that are dried or diseased.
When you cut off the foliage, the plant is encouraged to spend more energy on growing even more of it. This makes the plant healthier and larger.
Make sure not to prune more than 1/3rd of the plant at a time. Otherwise, it won’t have enough foliage to produce food for itself. It may also get stressed and die in severe situations.
I suggest using a bypass pruner when doing the pruning. They will help you get a clean cut and reduce the chances of infection. Make sure to clean them before and after use with rubbing alcohol.
Harvest the kohlrabi from the pots
The kohlrabi base will be ready for harvest after 45 to 60 days from the time you planted the seeds. This depends on the variety of kohlrabi that you are growing. So check the seed packet to know the exact dates.
You can harvest the leaves of the plant well before the base is mature. These leaves can be used as microgreens as part of your salads.
You need to harvest the kohlrabi when the base is 2-4 inches in size. If you leave them to grow larger, the kohlrabi will turn woody and bitter.
They will also turn bitter and crack if you leave them in the heat of summer. They are frost-tolerant so you can leave them in fall even after the first frost has hit your area.
To harvest the kohlrabi, you can use a knife and cut around the base of the plant. You can store the kohlrabi in a cool, dry place for several weeks.