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How To Grow Purple Kohlrabi Microgreens

Purple Kohlrabi

Brassica oleracea


Purple Kohlrabi (Brassica oleracea L. var. gongylodes L.) are super easy-to-grow, flavorful microgreens that make a fantastic base for any salad. The beautiful purple stems and bold green cotyledons (embryonic leaves) make them a perfect addition to any dish.

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Quick Facts:

  •  Common Name: Purple Kohlrabi

  •  Scientific Name: Brassica oleracea L. var. gongylodes L.

  •  Other Names: German turnip, Knol-khol

  •  Family Name: Brassicaceae

  •  Flavor: Mild Cabbage, Broccoli Flavor

  •  Seed Rate: 20g-25g per 10″ x 20″ tray

  •  Seeds Per in2: 0.1g-0.125g

  •  Avg. Yeild/1020 Tray: 275-315g

  •  Pre-Soak: No

  •  Weight Duration: 2-3 Days

  •  Germination Time: 2-3 Days

  •  Blackout Time: 2-3 Days

  •  Harvest Time: 8-12 Days

  •  Growing Difficulty: Easy

Did You Know


Scott Palmers Biggest Kohlrabi World Record

Scott Robb (USA) grew a world record-breaking kohlrabi, weighing in at 96.95 lb (43.98kg) at the Alaska State Fair, Palmer, Alaska, USA, on the 30th of August 2006.

Plant Details &

Grow Guide

How To Grow Purple Kohlrabi Microgreens

Purple Kohlrabi is one of the easiest microgreens you can grow. It’s gaining popularity due to its vibrant magenta to white-colored stems and beautiful contrasting cotyledons.

They have a slightly sweet, mild cabbage flavor. It’s a perfect addition to sandwiches and salads. Not only do they taste great but due to its gorgeous colors they’re perfect for making a dish pop as a garnish. They can be harvested anywhere from 8-12 days. So let’s get started!

Step 1 Measuring & Preparing Your Seeds

First, you need to measure your seeds using a scale. The best seeding rate for a 10″ × 20″ tray is 20-25 grams. If you plan to grow them in a 10″ × 10″ tray then simply divide the total amount by two, in this case, 10-12.5 grams.

You can also just eyeball it without weighing, just make sure that your seeds are approx ⅛-¼” (3-6mm) apart.

Once you’ve measured out your seeds you do not need to wash and pre-soak them. This is because the seeds are small about 2mm in diameter, and wetting them will make it harder in spreading them evenly on your growing medium.

Step 2 Sowing Your Seeds

Fill your tray with your preferred medium, it can be soil, potting mix, coco coir, etc, leaving 1-2cm of empty space from the tray edge to the soil level.

Leaving a small space between the tray edge and grow medium helps when it comes to harvesting, minimizing the chance of digging into the medium with your knife.

Make sure you level your medium with your hands so it’s not clumpy, you don’t want your seeds grouping together when you sow them.

First, mist your medium with a spray bottle so it’s damp but not saturated, I recommend this because when you sow your seeds they won’t bounce around and instead stick to the medium.

Spread your seeds across the medium making sure they’re evenly spread out. Lastly, mist your seeds so they’re all covered with a fine mist of water.

Step 3 Germination & Weight Period

Grab an empty tray with no holes and place it on top of your sowed seeds. I use a 15lb (6.80kg) paving block for 10″ × 20″ trays or a 7lb (3.17 kg) brick on 10″ × 10″ trays.

This helps the seed radicle to bury into the medium when it emerges. Without weight, the radicles have a tougher time digging into the growing medium.

Keep in mind that the seeds will germinate while they’re covered and weighed down. A lot of people confuse the germination and weight period to be independent of one another and that you add them together, this is incorrect.

The germination time is there to give you an idea by what time the seeds will germinate, but you don’t add the germination time and blackout period together.

While your seeds are germinating and are weighed down you will need to keep your medium moist. You can do this by lightly misting your seeds every 12 hours, once in the morning and once at night.

Step 4 Blackout Time

After 2-3 days of weight period, the seeds should have germinated and the seedlings should now be lifting the tray with the weight in it. It’s now time to remove the weight and start the blackout period.

Take out the weight from your empty tray and flip it upside down to create a blackout dome and place it back over your seeds.

Keeping them in the dark for 2-3 days will force the freshly sprouted seedlings to stretch and search for light allowing them to get some height.

You can now start bottom watering your microgreens. To do this you simply add water to your bottom drain tray. I personally add 1 cup of water twice a day (every 12 hours), once in the morning and once in the evening.

When the 2-3 days of blackout time have passed you can remove the top tray/blackout dome and introduce your microgreens to light. I’ve found that 17 hours under lights and 7 hours with the lights off work well for me.

Grow your purple kohlrabi anywhere from 8-12 days, following with daily watering of 2 cups per day, once every 12 hours.

Step 5 Harvest

Harvesting your purple kohlrabi microgreens is easy and you only need a sharp knife. I personally love and recommend the Green Mercer Produce Knife. If you prefer using scissors then you can’t go wrong with these heavy duty scissors!

Just make sure your knife or scissors are not coming into contact with your soil while you’re cutting to avoid contaminating your crop with dirt.

Plant Details & Taxonomy

Brassica oleracea L. var. gongylodes L. is a biennial, cool-season vegetable that belongs to the Brassicaceae family. Kohlrabi seeds weigh from 220-280 seeds per gram.

Purple kohlrabi microgreens have beautiful and vibrant purple stems with contrasting green cotyledons. They have a bold taste and crunchy texture similar to cabbage and broccoli, it’s a perfect addition to any salad, slaw, or sandwich.

SOURCE: The botanical data and taxonomic details were acquired from the USDA Plants Database

Rank Scientific Name
Kingdom Plantae – Plants
Subkingdom Tracheobionta – Vascular plants
Superdivision Spermatophyta – Seed plants
Division Magnoliophyta – Flowering plants
Class Magnoliopsida – Dicotyledons
Subclass Dilleniidae
Order Capparales
Family Brassicaceae – Mustard family
Genus Brassica L. – mustard
Species Brassica oleracea L. – cabbage
Variety Brassica oleracea L. var. gongylodes – kohlrabi
Common Names Purple Kohlrabi, Purple Kohlrabi Vienna, Knol-khol, German turnip

Microgreen Pests & Diseases

The following are the most common pests and diseases that can affect your microgreens.


White Mold – Sclerotinia sclerotiorum

Sclerotinia sclerotiorum is a necrotrophic fungal disease that causes what’s known as white mold, it can infect over 400 plant species worldwide. It’s also called cottony soft rot, stem rot, watery soft rot, crown rot, and seedling blight.

S. sclerotiorum key properties are its ability to create sclerotia which are its black resting structures, and mycelium which are the white fuzzy spiderweb-like growths you see on stems and growing medium.

microgreens suffering from damping off disease

Damping Off

Damping-off is an umbrella term that covers fungi and fungi-like organisms in several genera including Rhizoctonia, Botrytis, Phytophthora, and Fusarium, with the soil fungus Pythium being the often culprit.

Damping-off is a soil-borne fungal disease that affects seeds and seedlings typically by rotting of the stems and roots at and below the soil surface.

When a seed germinates the seedling will emerge fine but within 24 hours to a few days will become mushy and water-soaked, collapse at the base of the stem and die.

Aphids crawling on a plant stem

Aphids – Aphidoidea

Aphids suck! Quite literally. They’re soft-bodied insects that use their piercing-sucking mouths to feed on plants and there are over 4,000 aphid species in the world.

Other common names are greenflies, blackflies, and plant lice. They come in varying colors such as light green, black, white, brown, gray, or yellow.

When aphids feed on plants they secrete a sticky fluid which is called honeydew (no, don’t eat it). This goo they leave behind drips onto plants and can attract other pests such as ants. If the honeydew is left on leaves it can promote black sooty mold.

Purple Kohlrabi Nutrition Facts

Purple kohlrabi is an excellent source of vitamin C, providing 69% of the recommended daily allowance per 100g of microgreens.

They’re also high in fiber and contain a good amount of vitamin B-complex groups such as vitamin B1, B2, B3, and B-6. Lastly, it’s a great source of minerals such as Calcium, Copper, Iron, Magnesium, Phosphorus, and Zink.

Nutrition value per 100 g. (Source: USDA National Nutrient database)

PLEASE NOTE: Percent Daily Values are calculated based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

Principle Nutrient Value Unit RDA
Energy 23 Kcal 1%
Carbohydrates 0.33 g 0%
Protein 2.46 g 4%
Total Fat 2.46 g 4%
Cholesterol 0 mg 0%
Dietary Fiber 6.7 g 18%
Folate 85 µg 21%
Selenium, Se 0.9 µg 2%
Vitamin A 146 µg 195%
Vitamin B1 (Thiamin) 0.027 mg 2%
Vitamin B2 (Riboflavin) 0.158 mg 12%
Vitamin B3 (Niacin) 0.658 mg 4%
Vitamin B5 (Pantothenic acid) 0.064 mg 13%
Vitamin B-6 (Pyridoxin) 0.192 mg 15%
Vitamin C 43.3 mg 48%
Vitamin E 1.2 mg 8%
Vitamin K 1140 µg 950%
Sodium, Na 20 mg 1.33%
Potassium, K 611 mg 13.00%
Calcium, Ca 215 mg 21.50%
Copper, Cu 0.162 mg 18.00%
Iron, Fe 2.32 mg 29.00%
Magnesium, Mg 55 mg 13.41%
Manganese, Mn 0.885 mg 38.48%
Phosphorus, P 50 mg 7.14%
Zinc, Zn 0.9 mg 8.18%
β-Carotene, beta 0 µg 0.00%
α-Carotene, alpha 0 µg 0.00%
Lutein + zeaxanthin 0 µg 0.00%

Recommended Seed Providers

I highly recommend True Leaf Market and SeedsNow for all your seed needs. Their wide selection of high-quality seeds and exceptional customer service make them the go-to choice for both novice and experienced gardeners alike.

True Leaf Market

For over 45 years True Leaf Market has been a provider of high-quality seeds both GMO and NON-GMO organic seeds. They also provide phytosanitary certificates if you need to import seeds to a country outside of the US.


SeedsNow is a family-run company, with the aim of assisting individuals, families, and communities in preparing for the future through the promotion of an organic and self-sustainable lifestyle. All their seeds are completely free from any genetic modifications, making them heirlooms, open-pollinated (OP), raw, natural, and untreated. Additionally, they do provide a selection of hybrid varieties on their website which will be clearly labeled as such in the product listings.

Close up of purple kohlrabi seeds

Buy Purple Kohlrabi Microgreen Seeds

Purple Kohlrabi have beautiful purple stems and bold green cotyledons (embryonic leaves) that make them a perfect addition to any dish. Add a touch of freshness and a pop of color to your dishes by ordering purple kohlrabi microgreen seeds today.

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Green Microgreens Growing Trays

Microgreen Grow Trays

For my personal home use, these microgreen trays are my go to. Measuring around 12.2 x 9.06 x 1.77 inches (31 x 23 x 4.5 cm), these trays are perfectly suited for cultivating microgreens in a home microgreen grow room. What’s more, they’re durable, and cleaning them is a walk in the park, making them an all-around convenient choice.

1020 Microgreen Trays - Shallow Extra Strength Colors

1020 Microgreen Trays – Shallow Extra Strength Colors

Industry leading BootStrap Farmers 1020 microgreen trays! Designed with long lasting durability in mind, these colorful trays are built to withstand years of use and abuse. With a height of 1¼ inches (3.2 cm), these shallow trays make harvests easy, saving you time and increasing your yield. The trays come equipped with 36 drainage holes that effectively remove excess water, promoting a healthy growing environment and preventing mold growth. If you’re serious about growing microgreens and want the best trays available on the market, these trays are it!

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