Kohlrabi Kingdom: A Guide to Growing Kohlrabi at Home

Kohlrabi is an under appreciated vegetable that deserves a place in every gardener’s plot. This unique brassica offers crunchy, sweet-tasting bulbs that add delight to any dish. Read on to discover the many benefits of growing kohlrabi, along with practical guidance for nurturing a thriving crop right in your own backyard.

Why Grow Your Own Kohlrabi?

Growing your own kohlrabi provides several advantages over buying it at the store.

Nutritious and Delicious

Kohlrabi bulbs bursting with freshness contain higher vitamin and antioxidant levels compared to store-bought varieties. Their sweet, peppery flavor simply can’t compare to anything from the grocer’s shelf.

• Kohlrabi is an excellent source of vitamin C, providing 140% of your daily recommended intake in just one cup. Vitamin C boosts immunity and acts as an antioxidant to prevent cell damage.
• It also contains decent amounts of other vitamins and minerals like vitamin B6, potassium, copper, and manganese. These support nerve signaling, heart health, energy production, bone strength, and more.
• The phytochemicals glucobrassicin, gluconasturtiin, and glucoraphasatin give kohlrabi its pungent flavor. These compounds also offer anti-inflammatory, antifungal, and anticancer benefits.
• Studies show that organically grown kohlrabi has higher antioxidant levels compared to conventional varieties. So homegrown kohlrabi from your chemical-free garden is more nutritious.
• Freshly harvested kohlrabi, eaten within days of picking, provides superior texture and taste over grocery store kohlrabi which could be weeks old.

Cost-Effective

With just a small investment in seeds and soil amendments, you can harvest basketfuls of kohlrabi for mere pennies per bulb. Skip the steep price tags at the market and enjoy homegrown savings instead.

• A $3 packet of kohlrabi seeds can supply enough seedlings for a 20 ft row, which can yield over 50 bulbs. This comes out to just 6 cents a bulb compared to $2-3 each at the store.
• A bale of organic compost or fertilizer for your garden costs $30-50 but will nourish crops for years. Amortized over many harvests, soil amendments add just pennies to each kohlrabi bulb you grow.
• Large-scale monoculture farms rely heavily on chemical pesticides, fertilizers, mechanized irrigation, and more – costs that get passed onto consumers. But small-scale home gardening utilizes primarily organic methods which are far more affordable.
• You save significantly on grocery bills when supplementing store-bought produce with home-grown fruits and veggies. A few kohlrabi plants can generate 10+ pounds over a season.
• Additionally, you avoid the hidden costs to the environment and society from commercial agriculture’s resource exploitation and pollution.

Sustainable

Reduce your carbon footprint by eliminating transportation emissions and plastic packaging waste. Grow kohlrabi using organic methods to nurture your soil as well.

• Store-bought kohlrabi travels over 1500 food miles on average from farm to plate, burning fossil fuels all along the way. But your homegrown kohlrabi skips this carbon-costly journey, sprouting just steps from your kitchen.
• Commercially grown kohlrabi gets wrapped in single-use plastic clamshell containers destined for landfills. But your garden-fresh kohlrabi requires no packaging whatsoever.
• Large monoculture farm fields are heavily sprayed with synthetic fertilizers and pesticides that run off into waterways, disrupting ecosystems. But small-scale home gardens utilize primarily organic growing methods that nourish the soil and environment.
• Cover cropping, crop rotation, and compost applications in home gardens mimic natural cycles, increasing biodiversity, soil health, and climate resilience over the long term.
• Growing regionally-appropriate heirloom varieties preserves agricultural heritage and genetic diversity while increasing your self-sufficiency.

Educational

Kohlrabi serves as an excellent plant for teaching gardening basics, as it germinates readily and matures quickly. Kids delight in harvesting the funny-looking orbs.

• Kohlrabi has a relatively short growing season of just 45-60 days from seed to harvest. This allows children to witness the full life cycle over a summer compared to vegetables that take many months.
• The swollen stem bulb offers visual intrigue and whimsical appeal to children, who love to pull the “spaceship” kohlrabi from the soil. This hands-on experience connects them directly to their food’s origins.
• Kohlrabi will tolerate some benign neglect, making it more forgiving plant for novice gardeners learning the ropes. And quick germination provides positive reinforcement.
• Its rapid growth allows multiple successions to be sown just weeks apart. Kids can experiment planting kohlrabi at different times and track differences in size.
• Letting children select a fun kohlrabi variety to grow, care for their plant, and pick their own harvest instills responsibility, pride, and self-confidence.
• As an easy-to-grow, cool weather crop, kohlrabi extends the gardening season into spring and fall, offering more opportunities to teach children.

Preparing Your Kohlrabi Patch

A sunny spot with nutrient-rich, well-draining soil makes an ideal kohlrabi garden. Amendments may be required to create these conditions if your native soil is lacking.

Kohlrabi thrives with 6-8 hours of direct sunlight daily. Leafy greens will still grow with less sun but bulb formation requires strong light. Choose a south-facing location without large trees or buildings blocking sunlight.

This cool-weather-loving brassica prefers daytime temperatures of 60-70°F. In warm climates, plant an early spring and late summer crop to avoid heat stress. Kohlrabi can tolerate frosts but extremely cold temperatures will hamper growth.

Kohlrabi grows best in loose, crumbly soil rich in organic matter. Heavy clay or compacted soils will restrict bulb expansion, keeping them woody and tough. Here are tips for preparing optimal soil:

• Test your native soil’s texture, drainage, and nutrient levels. Based on the results, work in copious amounts of compost or aged manure to improve fertility, nutrition, moisture retention, and drainage.
• For heavy or dense soil, add gritty amendments like perlite, vermiculite, or sand to lighten the texture. Mix throughout the top 6 inches.
• Ideal pH range is 6.0-7.0. Add lime if soil is too acidic or sulfur if too alkaline.
• Before planting, rake beds smooth and remove any rocks, sticks or weed debris. Shape raised beds if drainage remains problematic.

When sowing seeds or transplanting seedlings, allow 4-6 inches between plants to accommodate their bushy nature. Interplanting with companion plants like beets or onions can deter pests too.

Companion plants offer synergistic benefits when grown alongside kohlrabi:

• Beets and onions mask the scent of brassicas, deterring pests like cabbage worms.
• Dill attracts beneficial predatory wasps that feast on aphids and other insects.
• Marigolds exude root secretions that repel nematodes in the soil.
• Lettuce and other leafy greens create living mulch to retain soil moisture and prevent weeds.

But avoid planting kohlrabi near potatoes, tomatoes, peppers, eggplants or strawberries, as these compete for nutrients.

Planting Kohlrabi Seeds & Seedlings

Kohlrabi can be started either from seed sown directly in the garden or transplanted outdoors as young seedlings after getting a head start indoors. Here is a comparison of both methods:

Sowing Seeds Outdoors

• Timing: Sow 2-4 weeks before your last expected frost date once temperatures warm to 45°F. Make small, successive plantings every 2 weeks for a continuous harvest.
• Planting Depth: Sow seeds 1⁄4-1⁄2 inch deep. Seeds need light to germinate so don’t plant too deeply.
• Spacing: Space seeds 2-4 inches apart in all directions since seedlings will be thinned. This allows you to select the strongest seedlings.
• Germination Time: Seeds germinate quickly in 4-7 days when soil temperature is at least 45°F.

Transplanting Seedlings Outdoors

• Timing: Start seeds indoors 4-6 weeks before your last frost date. Harden off and transplant outdoors 2 weeks before last expected frost.
• Containers: Sow 2-3 seeds per cell in biodegradable pots. Thin to one seedling per cell after sprouting.
• Soil: Use sterile seed starting mix and keep evenly moist. Grow seedlings under lights or sunny window.
• Hardening Off: Set seedlings outdoors in filtered light for a few hours daily over a week before transplanting.

Caring for Your Kohlrabi Crop

Proper care is vital for growing healthy, high-yielding kohlrabi plants. Here are key growing requirements to help your crop thrive.

Watering & Irrigation

Kohlrabi needs 1-1.5 inches of water weekly. Apply organic mulch to retain moisture while suppressing weeds.

• Kohlrabi has shallow roots so requires frequent irrigation, especially as bulbs swell. Uneven watering produces woody, bitter bulbs.
• Soak the soil thoroughly to a depth of 6 inches rather than frequent light sprinklings to encourage deep root establishment.
• Use a rain gauge or soil probe to monitor moisture levels. Avoid overwatering which causes disease and nutrient leaching.
• Consider drip irrigation or soaker hoses to direct water to the soil. This prevents fungal leaf diseases from moisture sitting on foliage.
• Apply 3-6 inches of organic mulch like straw, leaves, wood chips or grass clippings around plants to moderate soil temperature and retain moisture while reducing weed growth.

Fertilization

Side dress plants with balanced organic fertilizer or compost tea every 3-4 weeks.

• Kohlrabi needs consistent nutrients over its quick 45-day growth period. Fertilize too early causes excessive leafy growth rather than bulb swelling.
• Mix 1-2 tablespoons per square foot of balanced organic granular fertilizer (10-10-10 nitrogen-phosphorous-potassium ratio) into soil around plants.
• For a liquid boost, brew compost tea by steeping compost in water for 2 weeks then diluting this “compost extract” 1:5 before applying.
• After harvest, cut off foliage and mix it back into soil as “green manure” to return nutrients and organic matter.

Weed Control

Vigorous weeds compete with kohlrabi for water, nutrients and sunlight. Smother weeds early before they overtake crop plants.

Weed Prevention Tips

• Apply mulch after seeding/transplanting to block light which weeds need to germinate. Replenish as it decomposes.
• Cover young plants with floating row covers until established. Use garden pins to secure fabric tightly to edges.
• Plant closely spaced to create living mulch as leaves quickly fill in area. This shades out emerging weeds.

Weed Management Techniques

If weeds sprout, promptly pull by hand or shallowly cultivate top inch of soil to uproot plants while they are small.

• Gently hoe or hand pull weeds, taking care not to damage tender kohlrabi roots located close to the surface.
• Avoid deep cultivation which can slice crop roots. Never hoe once bulb stems start expanding.
• For heavy infestations, set a box over plants then carefully pour boiling water or organic horticultural vinegar over weeds.
• As a last resort if overrun by weeds, spray certified organic herbicide with corn gluten meal or clove oil (when bees aren’t present).

Pest & Disease Prevention

Scout regularly for common brassica pests like cabbage worms and flea beetles. Row covers or organic sprays can thwart hungry insects when caught early. Rotate planting sites to disrupt pest and disease cycles.

Insect Pests

Cabbage worms – small white butterflies lay eggs which become green caterpillars eating leaves. Remove by hand or apply Bt bacteria spray.

Flea beetles – tiny black insects that riddle leaves with holes. Deter with lightweight row cover or spray insecticidal soap.

Root maggots – larvae tunnel into roots stunting plants. Prevent by covering with row cloth until rooted.

Diseases

Clubroot – fungal infection stunts plants, swelling roots. Solarize soil to kill spores before planting.

Alternaria leaf spot – Produces brown target-like marks on leaves in wet conditions. Avoid overhead watering.

Prevention Methods

• Purchase disease-resistant varieties when available
• Disinfect tools between plants with diluted bleach
• Solarize soil under black plastic for 6 weeks before planting to kill pathogens
• Rotate plant families in growing beds on 3-year cycles avoiding replanting brassicas
• Cull diseased plants immediately, sealing in bag and removing from garden
• Control weeds where pests overwinter

Harvesting Kohlrabi

Determining Peak Harvest Time

Bulbs reach peak tenderness when 2-3 inches wide. The swollen stem should feel firm with crisp, shiny exterior free of blemishes or cracks. Large, overly mature kohlrabi becomes woody and bitter tasting.

Harvest just before using, as freshness rapidly declines after picking. Timely harvesting also allows the remaining plants to continuously produce new side shoots for later yields.

Check bulb size by gently pushing away leaves to reveal the swollen stem, being careful not to nick it. Another indication bulb is reaching maturity is when lower leaves yellow and drop off.

Let the plant size guide you rather than relying strictly on “days to maturity” statistics which vary significantly depending on growing conditions.

You can begin harvesting kohlrabi as early as 3 weeks after germination if started in spring. But late summer plantings often take a week or two longer due to cooler temperatures and weaker sunlight.

Once kohlrabi stem expands beyond 3 inches across or if overmature specimens develop woody fibers, pull out the entire plant to allow younger ones more room to continue growing. The leaves, peeled stem and bulb all remain edible at any stage.

Harvest Methods

Harvest kohlrabi using the following techniques:

Gently loosen soil with a garden fork tine inserted 2 inches from base of the plant. This fractures surface roots. Firmly grasp lower leaves in one hand. Apply upward pressure, rocking slightly until bulb releases from soil. Take care not to break stems off bulbs when pulling as they don’t store well.

Alternatively, slice bulbs off just below soil line with a sharp knife, leaving some leaves and roots still in ground. This rapid harvest method works great if a killing frost is imminent. The plant will often produce several smaller side bulbs at the base which can be gathered a few weeks later.

After lifting entire plants, use clean, sanitized pruning shears to trim back leaves, leaving about an inch of stem attached to bulbs. Rinse off soil then pat dry with a towel. Remove any browned or damaged outer layers on the stem using a paring knife before storing.

Storing Your Kohlrabi Harvest

Cured kohlrabi stores 2+ weeks in the crisper drawer. Wrap bulbs in plastic for long-term freezer storage.

To extend shelf life after harvest, cure kohlrabi for 1-2 weeks in a dark cool place like a garage or basement around 55°F and 70% humidity. This allows sugars to concentrate while the skin further toughens up creating a protective barrier to moisture loss. Careful not to cure too long or bulbs will become pithy.

Check regularly during curing to remove any specimens showing signs of shriveling or mold before it spreads.

For short term storage up to 2-3 weeks, place cured, trimmed bulbs in perforated plastic bags in the hydrator drawer of the refrigerator. Do not wash until ready to eat, as excess moisture hastens spoilage.

For long term freezer storage, prepared bulbs will last 9 months or longer. To freeze:

1. Clean, peel and chop kohlrabi into 1⁄2” cubes.
2. Blanch cubes for 3 minutes then shock in ice bath to stop cooking.
3. Pat very dry then spread pieces in single layer on sheet pan. Freeze solid overnight.
4. Transfer frozen pieces into labeled freezer bags, squeezing out air pockets before sealing.

Frozen kohlrabi maintains its texture and taste well when cooked frozen without thawing first.

Enjoying Your Kohlrabi Bounty

Beyond its sweet crunch eaten raw, kohlrabi shines in everything from fresh slaws to roasted veggie medleys. Its mild flavor mixes well with assertive seasonings too. Try this tasty, nutrient-dense crop if you haven’t already – your taste buds will thank you.

While often consumed raw for its signature crunchy juiciness, kohlrabi also excels when cooked. Roasting coaxes out kohlrabi’s natural sweetness and intensifies flavor. Quick steaming retains beneficial nutrients yet softens tough fibers. You can substitute kohlrabi in most recipes calling for turnips, broccoli stems, or radishes. Those funky-looking orbs offer amazing versatility.

Explore creative ways you can prepare your homegrown kohlrabi using the following recipes:

Kohlrabi Apple Slaw

• Thinly shred 1 bulb kohlrabi and 2 apples. Toss with lemon juice and olive oil. Mix with chopped parsley, toasted nuts, raisins and top with apple cider vinaigrette.

Roasted Garlic Kohlrabi Mash

• Roast chopped kohlrabi and whole garlic bulbs drizzled with olive oil. Mash with butter and cream.

Kohlrabi Fries

• Slice bulbs into thick wedges, toss with olive oil, cumin, paprika, salt and pepper. Roast at 425°F until crispy, about 15 minutes per side.

Creamy Kohlrabi Soup

• Sauté chopped onion and celery in butter. Add broth, diced kohlrabi, thyme, nutmeg, salt and pepper. Simmer 25 minutes until kohlrabi is very tender. Purée until smooth then swirl in heavy cream. Garnish bowls with crunchy toasted walnuts.

Kohlrabi Noodle Salad

• Use vegetable spiralizer to cut kohlrabi into noodle-like ribbons. Toss with chopped cucumber, red bell pepper, green onions, fresh basil and mint. Dress with rice vinegar, soy sauce, sesame oil, lime juice and toasted sesame seeds.

Baked Kohlrabi Chips

• Peel bulbs then mandoline slice into 1/8” thick rounds. Toss with olive oil, cumin, chili powder and salt. Bake at 275°F, flipping once until crispy, about 90 minutes total.

Braised Kohlrabi Greens

• Remove leaves when harvesting bulbs. Chop leaves and stems then braise in broth with garlic and red pepper flakes until tender, 15-20 minutes. Toss with lemon juice and grated Parmesan.

And here are a few simple ideas for whipping up kohlrabi:

• Grate raw bulbs over grain bowls and green salads.
• Pickle peeled cubes in vinegar brine with whole spices.
• Sauté matchstick pieces to toss into fried rice or noodle dishes for crunch.
• Purée steamed kohlrabi with broth and cream as a mashed potato substitute.

So don’t let those unusual-looking orbs intimidate you! Kohlrabi is fun to grow and offers a tasty, versatile veggie harvest that keeps giving all season long.