How do you Grow Kohlrabi from Seed?
This can be a difficult question to answer for beginner vegetable gardeners because of numerous factors including climate, soil, and experience level.
This article will help solve this problem and give beginner gardeners Easy-to-Follow Steps on growing kohlrabi from seed.
And I recommend scrolling to the bottom of this page to find answers to the 7 most frequently asked questions most gardeners have when growing kohlrabi.
Step #1: Plant 2 Types of Kohlrabi
I am recommending two types of kohlrabi that are simple to grow and care for regardless of your experience.
A) Purple Kohlrabi
- Scientific Name: Brassica Oleracea
- Length & Width: 2 feet x 2 feet
- Hardiness Zone: 5 – 7
- Harvest: June
Purple Kohlrabi is an excellent vegetable for anyone who wants a low calorie, high fiber, and high vitamin food.
This vegetable is incredibly easy to plant & grow, with no fertilizing needed. You should water your kohlrabi daily, take precautions to prevent pests, and provide partial-sunlight.
The tast eof purple kohlrabi is slightly sweet and many gardeners say it resembles the taste of a radish.
B) White Kohlrabi
- Scientific Name: Brassica Oleracea (gongylodes)
- Length & Width: 2 feet by 2 feet
- Hardiness Zone: 5 – 7
- Harvest: June
There is really no difference between purple and white kohlrabi. You grow them the same, care for them the same, and even use them the same.
It should be noted that white kohlrabi has a slightly sharper taste than purple kohlrabi. You’ll notice that white kohlrabi tastes a bit more like cabbage.
Regardless of the taste, white and purple kohlrabi will provide gardeners with the same vitamins and minerals.
Step #2: Start Your Seeds Indoors
When learning how to grow Kohlrabi from seed you should always start indoors. This will help minimize the risk of weather, pests, and disease.
Step 1 – Begin Planting 12 weeks Before the Last Frost
You will want to start your seeds inside approximately 12 weeks before you plan on moving your Kohlrabi into your garden or moving your planter outside.
- You will first want to start by buying your seed. I recommend buying from Amazon because it is quick and inexpensive.
- You will then want to take 3-inch GrowKo Peat Pots and fill them up to approximately 80% full with Miracle-Gro Potting Mix.
- Next, spray your soil 5 to 8 times with a spray bottle. You will want the soil to be moist, not damp. Damp soil can cause unwanted fungus.
*Find Your Last Frost Date HERE*
Step 2 – Plant 2 to 3 Seeds Per Pot
- Sprinkle 2 to 3 seeds per pot about 1/8 inch deep and then gently brush the soil over the seeds. *Note, do not bury the seeds.
- Then spray the soil again 5 to 8 times until it turns a dark color.
Step 3 – Provide Your Seeds with At Least 8 Hours of Sunlight
- After planting your seeds, provide at least 8 hours of sunlight by placing the pots by a window or a Grow Light if your windows do not receive enough sunlight.
*If you put your seeds closer than 4 inches they will burn and die. If you put them further away than 4 inches there is a chance they won’t get enough sun to germinate.*
You will also want to keep the room temperature at approximately 70 degrees Fahrenheit
- This is the temperature needed so that your seeds can turn into plants.
If you don’t have an area that will stay consistently around 70
- A Plant Heating Mat is the perfect way to keep your pots and seeds at a consistent temperature that we may not otherwise be able to.
Step 4 – Spray, Spray, Spray
After your initial planting, you will need to spray the soil once to twice a day for approximately 2 weeks
It will take approximately 2 weeks for your seeds to germinate or “pop” through the soil.
Once your seeds have germinated and sprouted through the soil, you will want to continue to spray them twice a day for 2 more months until they are about 3 inches tall.
Step 5 – Transplant your Kohlrabi Plant into a Larger Pot
Once your kohlrabi is 3 inches tall you can transplant it into your 5 Gallon Nursery Pot.
Again, you will want to fill these pots about 80% full with your potting mix.
Next, you will want to make a hole approximately 3 inches deep (about the size of your kohlrabi plant at this point).
Then turn your existing small pot upside down, pinch the bottom of it, and then gently pull the soil and your plant out.
You will then place it in your 5-gallon pot and fill it with soil.
Immediately after you do this, spray the soil about 5 to 10 times.
Step 6 – Introduce your Kohlrabi to Outside Weather
This next step is what most beginner gardeners miss, but is critical to your success.
For about two weeks, you will want to slowly introduce your Kohlrabi to the outside.
On the first day, you will want to place your Kohlrabi (still in its pot) outside in direct sunlight for approximately 2 hours.
Each day thereafter, place the Kohlrabi outside for an additional hour until you build up to 6 straight hours.
Step #3: Transplant Your Kohlrabi Outside
Once the last frost of the year has happened you can transplant your Kohlrabi outside.
Below, is a 2 step process for transplanting your Kohlrabi outside into your garden.
Step 1 – Apply Compost if you will be keeping your Kohlrabi in its container all summer!
If you decide to keep your Kohlrabi in the pots then there is no need to transplant. You will only need to apply compost or Miracle-Gro Potting Mix
- Apply approximately 1/4 inch of potting mix to your planter
- As soon as you apply your fertilizer make sure to water the Kohlrabi for approximately 15 to 20 seconds
- Every week until harvest water your kohlrabi once or twice a day (depending on the amount of sun and temperature it receives).
If you want to learn more about growing Kohlrabi in containers, I recommend watching the below video:
Step 2 – Transplant your Kohlrabi into Your Garden
- About 1 month before you plan on transplanting your kohlrabi into a garden dig holes about 8 inches deep and filling it with compost or Besgrow Sphagnum Moss. Space holes 8 inches apart.
- Dig your holes in an area that will receive at least 8 hours of light.
- Then after the last frost transplant your kohlrabi into the garden exactly the same way you transplanted it into the larger pots.
- Immediately after you transplant your kohlrabi outside add
Miracle-Gro Plant Food and water the soil for about 30 seconds.
- Finally, water your Kohlrabi once to twice a week. Kohlrabi has a strong drought resistance, so if you forget sometimes it’s okay.
- Related To: Best Garden Hoses
Step #4: Properly care for your Kohlrabi
Below are caring tips for your Kohlrabi throughout the summer:
- Keep Your Soil Healthy – Quickly inspect your soil for fungus, harmful worms, and weeds before you plant and throughout the summer. Remove and replace it with new soil as needed.
- Safeguard Against Insects. Especially beetles and worms. They can quickly ruin a good crop of Kohlrabi within two days. If you don’t want beetles ruining all your hard work I recommend purchasing Sevin Bug Killer.
- Water Twice a Week. Water twice a week. Like most green leaf plants, you cannot overwater your kohlrabi.
Step #5: Effectively Harvest Kohlrabi!
Below are several tips to remember when harvesting kohlrabi:
- Morning is the best time to harvest your kohlrabi.
- Dig under your kohlrabi vegetable to harvest it. This will prevent you from knicking your vegetable.
- After harvesting your kohlrabi you can cut off the stalk and keep the root vegetable.
Frequently Asked Questions (7 Questions)
1. What are the Best Uses for Kohlrabi?
Below, are a few of the uses of kohlrabi that are both easy and most enjoyable:
- Food: I could bore you with some simple and effective recipes, but why do that when you can read about 5 Tasty Kohlrabi Recipes HERE.
- Compost: The leaves of Kohlrabi are great for adding green waste to compost that will quickly decompose.
- Livestock Food: The leaves of Kohlrabi are also great for feeding livestock like goats, sheeps, and even other farm and homestead animals.
2. What Is the Best Way to Store Kohlrabi?
Below, are the best ways to store your Kohlrabi:
- Fresh kohlrabi will last approximately 2 weeks.
- Kohlrabi kept in a refrigerator will last only slightly longer, approximately 3-4 weeks.
- And I recommend not freezing kohlrabi. Like many other vegetables, when unfrozen this vegetable will become soggy and not tasty.
3. What type of Seed Should I buy?
Purchasing kohlrabi seeds is a much easier task than say tomato seeds, where you have to worry about GMOs, Organic, Heirloom, etc.
When buying kohlrabi seeds you should stick to traditional or heirloom. These will give you the best success in growing Kohlrabi.
Just as important is where you buy your seeds from. I recommend buying your seeds from Amazon. This will provide you with the best price and quickest delivery.
4. What Type of Gardening Pot Should I Buy?
I recommend buying two sizes of pots.
First, buy 3-inch Peat Pots.
- You’ll typically get 25 to 50 seeds in a pack, so you’ll want to make sure to purchase enough pots. Also, you’ll typically lose about 20% of these plants to weather, disease, and pests.
Second, buy 5-gallon pots.
- This is essential if you want to allow your kohlrabi to grow to its fullest. It is also important if you want to continue to grow your kohlrabi outside.
5. What Type of Garden Soil Should I Use?
When planting kohlrabi the only type of soil you’ll need is potting mix.
- Very simply, this soil will contain the right mixture of soil, sand, and nutrients needed for your Kohlrabi seeds to grow healthy.
- It has everything needed to not only start seeds but to continue to grow your Kohlrabi if you decide not to transplant into your garden.
- Secondly, if you do decide to transplant into your garden this soil can mix right in with garden soil without affecting Kohlrabi or those plants around it.
6. What Type of Fertilizer Should I Use?
When planting kohlrabi the only type of fertilizer you’ll need is Besgrow Sphagnum Moss.
- What I love about this product is that it is incredibly clean, is stored in maintained swamps, and contains everything your Kohlrabi seeds need to flourish.
- Related: Winter Composting
- Related: Ultimate Composting Guide: What to Compost
7. What Gardening Tools do I need to Grow Kohlrabi?
You will want to make sure you have gardening gloves, pruners, a small hand shovel, and a bottle sprayer
For this, I recommend Vremi 9 piece toolset
- What makes this really a great purchase is that all the tools are built with rust-resistant materials, comfortable handles, and a great way to carry it to and from your garden.
