Winner Kohlrabi
Winner is a widely recommended kohlrabi for home gardens: 45-50 days to maturity, slow to become pithy, and reliable across zones 5-9. Harvest at 2-3 inches diameter for best texture. Kohlrabi is one of the easiest and fastest brassicas, with an above-ground swollen stem rather than a root. It can be direct sown, succession-planted every 2-3 weeks, and grown across a wider temperature range than most heading brassicas. Harvest promptly because oversized bulbs become woody and bitter, especially in warm spring weather; fall-harvested bulbs can usually size a little larger. Useful comparison varieties include Quickstar, Grand Duke, and White or Purple Vienna. Key facts: 45–50 days to maturity, 6+ hours of sun, 6 " spacing. Container-friendly (minimum 1-gallon pot).
At a Glance
The essentials first: timing, light, spacing, seed-starting, container fit, and overall size.
Zone Planting Guide
Switch zones to see whether this plant is a strong fit, what frost timing looks like, and any extra notes worth planning around.
This card updates instantly with viability, frost timing, and any planting notes for your selected zone.
Growing Guide
Everything in one place: seed starting, transplant timing, watering, soil, and structural support.
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Jevrench Ultra Fine Garden Netting (4'x25')
Fine mesh blocks cabbage moths and flea beetles without chemicals. Lay over hoops at transplant time and leave on all season.
Plant Health
Stress tolerance, resistance notes, and the most common problems to watch for as plants mature.
Common Issues
Cause: Oversized stems, heat, or drought stress make bulbs pithy and bitter.
Prevention: Harvest at 2-3 inches and keep growth steady.
Cause: Caterpillars chew leaves and slow early growth.
Prevention: Use row cover after seeding or transplanting and scout leaves regularly.
Cause: Soilborne disease distorts brassica roots and stunts plants.
Prevention: Rotate away from brassicas and maintain good drainage.
Nutrition & Harvest
How hungry the plant is, what ripe harvest looks like, and how long the crop keeps after picking.
Bulb 2-3 inches diameter, firm. DO NOT let grow larger — becomes woody and bitter.
Companion Planting
Helpful neighbors can support growth or deter pests. Keep antagonistic plants separated to reduce stress and competition.
Planting reminders for Winner Kohlrabi
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Growing Supplies
Based on Winner Kohlrabi's growth profile -- recommendations matched to this variety's specific requirements.
Cool-season brassica seed-starting tray
UMN Extension says gardeners should start cabbage indoors for a spring-planted summer crop because a late direct-seeded crop would mature during the hottest part of summer, reducing quality. Transplants get crops out of the ground and into early production. Note that brassicas are cool-season crops and germinate well at 60 to 75 degrees Fahrenheit, so a heat mat is not necessary and can actually push germination too fast and produce weak seedlings. Use the cell tray and grow light, but skip the heat mat for brassica starts.
Source: UMN Extension
VIVOSUN Seedling Heat Mat (10"x20")
The foundation piece. UL & MET certified, 27,000+ reviews. Slides under any tray to boost germination rates for warm-season seeds.
View on AmazonVIVOSUN Heat Mat + Thermostat Combo
Same trusted mat with a digital thermostat so you can dial in exact soil temperature. Peppers want 80-85°F, tomatoes 75-80°F.
View on AmazonAC Infinity Heavy-Duty Germination Kit
Complete germination station with Samsung LEDs, 3mm thick dome, heat mat, and ventilation panels. The setup serious seed starters graduate to.
View on AmazonSeed starting tray + heat mat
For gardeners who start seeds indoors, this combo improves even germination. Warm-season crops benefit from bottom heat. Look for a rigid tray, cell inserts with drainage, and a heat mat paired with a thermostat.
Source: Utah State University Extension; Iowa State University Extension; Mississippi State University Extension
VIVOSUN Seedling Heat Mat (10"x20")
The foundation piece. UL & MET certified, 27,000+ reviews. Slides under any tray to boost germination rates for warm-season seeds.
View on AmazonVIVOSUN Heat Mat + Thermostat Combo
Same trusted mat with a digital thermostat so you can dial in exact soil temperature. Peppers want 80-85°F, tomatoes 75-80°F.
View on AmazonAC Infinity Heavy-Duty Germination Kit
Complete germination station with Samsung LEDs, 3mm thick dome, heat mat, and ventilation panels. The setup serious seed starters graduate to.
View on AmazonMulch / landscape fabric
Nearly every garden benefits from mulch for weed suppression, moisture conservation, and soil temperature moderation. For most home gardeners, quality organic mulch is the better buy over landscape fabric.
Source: Penn State Extension; Wisconsin Horticulture; Illinois Extension
EZ-Straw Seeding Mulch (1 cu ft, covers ~250 sq ft)
Processed wheat straw with biodegradable tackifier for slope retention. The most-reviewed garden straw on Amazon (1.8K+ reviews). Covers about 250 square feet at proper 2 to 3 inch depth, which fits a typical home raised-bed setup. Apply after seedlings are established and soil has warmed.
View on AmazonHealthiStraw GardenStraw (3 cu ft, ~20 lbs cleaned wheat straw)
Thoroughly cleaned wheat straw at 3 cubic feet, marketed specifically for vegetable gardens rather than animal bedding or decoration. Better per-pound economics than the 1 cu ft option, with the same extension-recommended material. Strong sales volume (2K+ bought past month) supports product consistency.
View on AmazonUSA Pinestraw Long Needle Pine Straw (covers ~100 sq ft)
Long-needle pine straw harvested in the US, premium type that decomposes more slowly than wheat straw. Pine straw is the regional preferred mulch in the humid Southeast (recommended by NC State, UF/IFAS, and Texas A&M extension) because it resists matting in heavy rain and stays in place better than chopped straw. Best for Zones 7a-9b vegetable beds.
View on AmazonDrip irrigation / soaker hose kit
Every gardener benefits from putting water at the root zone instead of on the leaves, because drip and soaker systems reduce foliar disease pressure by limiting leaf wetness and soil splash. A quality kit should include a backflow preventer, filter, pressure reducer, and UV-resistant tubing.
Source: Iowa State University Extension; Colorado State University Extension; UMass Extension
MIXC Quick-Connect Drip Starter Kit
Right-sized for 1-2 raised beds. Quick-connect fittings, adjustable nozzles, and 1/2" + 1/4" tubing included.
View on AmazonCARPATHEN Complete Garden Drip Kit
Designed for beginners with a step-by-step setup guide. Adjustable emitters, both tubing sizes, and all connectors included.
View on AmazonRain Bird Landscape Drip Irrigation Kit
Professional-grade from the company that builds irrigation systems for golf courses and farms. Includes drippers, micro-bubblers, and micro-sprays.
View on AmazonRow cover / frost blanket
Row cover adds frost protection, speeds early growth, and physically excludes insect pests without spraying. Look for spun-bonded fabric with a stated weight and frost rating, UV resistance, and enough width for hoops or low tunnels.
Source: University of Maryland Extension; University of New Hampshire Extension; Colorado State University Extension
Agfabric Floating Row Cover (5'x25')
Lightweight 0.9 oz fabric for light frost and pest exclusion. Breathable enough to leave on all season without overheating plants.
View on AmazonAlpineReach Frost Blanket (10'x30')
Thicker 1.2 oz fabric rated to protect down to 28°F. Covers 300 sq ft — enough for multiple raised beds in a single sheet.
View on AmazonDeWitt Supreme Crop Protection (6'x50')
Professional-grade 1.5 oz fabric from the brand farms and extension offices use. Handles hard freezes and lasts multiple seasons.
View on AmazonGarden shade cloth
K-State Research and Extension and University of Maryland Extension recommend shade cloth as a heat-management tool for vegetable gardens, with 30 percent shade rating most effective for tomatoes, peppers, and fruiting crops, and 40 to 50 percent for protecting heat-sensitive greens during hot summer months. University of Delaware research found 30 percent black shade cloth tripled marketable yield for bell peppers compared to unshaded plants, and Purdue trials showed shade cloth reduced maximum daily temperatures by 8 to 10 degrees Fahrenheit. Choose knitted polyethylene with reinforced grommets every 18 to 24 inches, mount on hoops or a frame with open sides for airflow, and remove or vent during prolonged wet weather to avoid increased humidity in the canopy.
Source: K-State Research and Extension; University of Maryland Extension; University of Delaware Cooperative Extension; Purdue University Extension
Agfabric 30% Sun-Block Shade Cloth (6 ft x 8 ft, with clips)
30 percent shade rating, the extension-recommended density for tomatoes, peppers, and other fruiting crops. Agfabric is one of the most-cited horticultural shade cloth brands. Includes clips for fast install over hoops or a simple PVC frame. Best for one raised bed or a small group of containers.
View on Amazonvensovo 30% Sunblock Shade Cloth (6 ft x 10 ft)
Same 30 percent rating in the typical home-garden size that fits a 4 by 8 raised bed plus working overhang. Knitted polyethylene with grommets for tie-down. Strong volume signal (3.8K reviews) supports consistent product quality across orders.
View on AmazonCoolaroo 30% UV Block Garden Shade Cloth (6 ft x 15 ft roll)
Coolaroo is the gold-standard horticultural shade fabric brand, used by professional growers and university research stations. Tear-resistant breathable knit at the same 30 percent rating, sized as a 6 by 15 foot roll for serious gardens with multiple beds. Cut to fit, secure with clips or grommets at the edges.
View on AmazonReflective plastic mulch (white-on-black or silver)
North Carolina State Extension reports that white-on-black plastic mulch can reduce soil temperature by 5 to 20 degrees Fahrenheit and silver mulch by about 6 degrees, the opposite effect of black mulch which warms soil. This makes reflective mulch the appropriate plasticulture choice for hot zones (especially Zone 9a desert and other high-heat low-humidity areas) where overheating limits warm-season crop performance more than cold soil. Silver mulch adds documented aphid and thrips repellency from the reflective surface. Use only with drip irrigation installed underneath, never use plastic mulch without irrigation, and reserve for late spring or early fall plantings where the surrounding heat is the primary stress.
Source: North Carolina State Extension; University of Arizona Cooperative Extension
Grower's Solution White on Black Plastic Mulch (4 ft x 100 ft, 1.0 mil)
1.0 mil embossed white-on-black mulch film at home-garden roll size. The white-up face reflects sunlight and reduces soil temperature 5 to 20 degrees F per NCSU; the black-down face suppresses weeds and prevents light from reaching the soil. Same proven Grower's Solution film used in our black/red mulch picks.
View on AmazonGrower's Solution Silver Metallic Plastic Mulch (4 ft x 100 ft, 1.0 mil)
1.0 mil embossed silver metallic mulch film. Silver provides about 6 degrees F of soil cooling per NCSU plus documented aphid and thrips repellency from the reflective surface — a dual benefit white-on-black does not offer. Best for desert and high-heat zones where pest pressure is also a concern.
View on AmazonGrower's Solution Silver Metallic Plastic Mulch (4 ft x 250 ft, 1.0 mil)
Same silver metallic film at 2.5x the length for only a few dollars more. Better per-foot economics for gardeners with multiple beds or planning multiple seasons of use. Store unused portion rolled and dry between seasons.
View on AmazonSoil test kit
A soil test gives a baseline for pH and nutrient status so gardeners can add only what the soil actually needs. Prioritize a mail-in or lab-affiliated kit whenever possible because extension guidance notes that laboratory testing is more accurate than instant readers.
Source: University of Maryland Extension; Purdue Extension; Montana State University Extension
Garden Tutor pH Test Strips
Quick pH checks for regular monitoring. 100 strips with an AI-powered reader for easy results.
View on AmazonRapitest 4-in-1 Soil Test Kit
The home garden standard. Tests pH, nitrogen, phosphorus, and potassium with a patented color comparator.
View on AmazonMySoil Professional Lab Test
Mail-in lab analysis covering 13 nutrients plus pH. Includes custom fertilizer recommendations for your soil.
View on AmazonSoil thermometer
University of Minnesota Extension recommends measuring soil temperature 2 to 4 inches below the surface to decide when warm-season crops can actually be planted, because air temperature and average frost dates do not reliably predict whether soil is warm enough for germination. A dedicated soil thermometer with a 4 to 6 inch stainless steel probe gives gardeners a deterministic reading instead of relying on the calendar alone, which matters most in zones with wide last-frost variability. Look for a waterproof stainless steel stem, a clearly marked vegetable-garden temperature range, and a readable analog or digital display at planting depth.
Source: University of Minnesota Extension
REOTEMP K82-3 Soil Thermometer (5" stem)
5-inch waterproof stainless steel stem, 0-220°F range. Purpose-built for seeding and transplanting decisions, not a multi-meter combo. Established US instrument brand with consistent accuracy reviews.
View on AmazonSmart Choice Stainless Steel Soil Thermometer (5" stem, 1.5" dial)
5-inch (127mm) stainless steel stem, 0-220°F range, 1.5-inch easy-read dial. Stronger review count and slightly larger display than the budget option, with the same temperature range.
View on AmazonVeeGee Stainless Steel Soil Thermometer (6" stem, 3" dial)
6-inch stainless steel stem with a large 3-inch glass-covered dial, ±2°F accuracy with 2°F subdivisions, calibration adjustment, 1-year warranty. The most readable and most accurate of the three; best for older eyes or quick spring readings without bending close.
View on AmazonSoil moisture meter (root-zone probe)
University of Arizona Cooperative Extension notes that most vegetables root in the top 12 to 24 inches of soil and that hot, dry periods require more frequent irrigation, but watering by habit often wets only the top inch while leaving the root zone dry. A dedicated soil moisture meter with a long probe gives gardeners a deterministic reading at root depth instead of guessing from surface appearance, which is most critical in low-rainfall desert zones (Zone 9a Phoenix) and in raised beds or containers that dry from the top down. Look for a single-purpose moisture meter (not a 3-in-1 or 4-in-1 combo, which trade accuracy for feature count) with a probe that reaches 8 to 12 inches and a clear analog or digital display.
Source: University of Arizona Cooperative Extension
XLUX Soil Moisture Meter (Since 2015, stainless steel probe)
The original XLUX moisture meter with a 304 stainless steel probe — won't corrode in alkaline desert soils or humid Gulf Coast beds. Single-purpose tool, no batteries required, instant-read dial. The most-reviewed soil moisture meter on Amazon (66K+ reviews, 7K+ bought past month). Best entry-level choice when probe durability matters more than maximum depth.
View on AmazonXLUX Long Probe Deep Use Soil Moisture Meter (single, 12-inch probe)
Extended 12-inch probe specifically designed to reach the 8 to 12 inch root zone where University of Arizona Extension recommends measuring. Critical for Zone 9a desert gardens, raised beds, and large containers where surface moisture readings don't reflect actual root-zone water status.
View on AmazonXLUX Long Probe Deep Use Soil Moisture Meter (2-pack, 12-inch probe)
Same 12-inch deep-use probe in a 2-pack for gardeners with multiple beds or who want to leave one meter staged in a primary bed and one for spot-checking. Better per-unit economics for serious desert gardens or any setup with separated growing areas.
View on AmazonStorm tie-downs and ground anchors
UF/IFAS Extension and Texas A&M AgriLife Extension recommend securing or removing trellises, shade cloth, hoop covers, container plants, and lightweight raised-bed accessories before tropical storms and hurricanes, since loose garden items become projectiles in high winds. Most-relevant for Gulf Coast Zone 8b (Houston, Mobile, New Orleans), Florida Zone 9b (Miami, Tampa), and any coastal area within the Atlantic and Gulf hurricane corridors. Galvanized steel ground anchors resist rust in humid coastal soils, and screw-in spiral anchors hold significantly better than driven stakes in saturated soil during storm conditions. Use quick-release fasteners on shade cloth and trellises so they can be removed quickly when a storm watch is issued.
Source: UF/IFAS Extension; Texas A&M AgriLife Extension
Eurmax USA 10-Pack Galvanized Tent Stakes with 4 x 10 ft Ropes
Galvanized steel canopy anchors with included rope — the only listing in this category that bundles stakes and tie-down rope together. Rust-resistant for humid Gulf Coast and Florida soils. The most-reviewed tent anchor on Amazon (12K+ reviews). Best as a starter kit for securing shade cloth, lightweight hoop covers, and trellises.
View on AmazonFEED GARDEN 12 inch J-Hook Rebar Stakes (16-pack, galvanized)
12 inch galvanized rebar stakes with a J-hook top, which lets gardeners loop rope or strap directly onto the stake for fast tie-downs. 16-pack covers a typical home garden's worth of trellises, shade frames, and hoop covers with stakes to spare. Better tie-down geometry than U-shaped stakes for storm prep.
View on Amazon30 inch Screw-In Heavy Duty Ground Anchors (4-pack, fully welded)
30 inch fully-welded spiral earth anchors that screw into soil rather than being driven. Spiral threads grip far better than straight stakes in saturated soil during storms, which is the failure mode that lets driven stakes pull free in high winds. This is the anchor type UF/IFAS hurricane prep guidance actually describes for Florida and Gulf Coast use. 4-pack covers the corners of a typical garden structure.
View on AmazonQuality bypass pruners
Extension guidance favors bypass designs because they make cleaner, closer cuts on living tissue than anvil types. Look for hardened steel blades that can be sharpened, a comfortable grip, and a cutting capacity matched to real home-garden stems.
Source: University of New Hampshire Extension; Iowa State University Extension; Purdue University Extension
gonicc 8" Professional Bypass Pruners
Titanium-coated blade, 5/8" cut capacity. Over 37,000 reviews and a consistent best seller for a reason.
View on AmazonCorona BP 3180D Forged Classic
Forged steel, 1" cut capacity. Corona has been making garden tools since 1928. The forged blade holds its edge longer than stamped alternatives.
View on AmazonFelco F5 All-Steel Bypass Pruner
Swiss-made, replaceable blade, spring, and every moving part. The buy-once pruner that professional growers reach for.
View on AmazonRaised bed kit
Raised beds improve drainage, let gardeners control soil from day one, reduce compaction, and make gardening more accessible. A quality kit should use rot-resistant, food-safe materials and provide enough depth for productive rooting.
Source: Penn State Extension; University of Delaware Cooperative Extension; Illinois Extension
Best Choice Products 8x4x2 ft Galvanized Metal Raised Bed (478-gallon)
Galvanized steel, 8 ft x 4 ft x 2 ft (24 inches deep). Non-toxic galvanized coating, rust-resistant for humid Gulf Coast and South Florida use. The most-reviewed metal raised bed on Amazon (5.6K reviews, 700+ bought past month). 24-inch depth supports deep-rooted vegetables like tomatoes and root crops.
View on AmazonGreenes Fence Premium Cedar Raised Garden Bed (4 ft x 8 ft x 17.5 in, 3/4 in thick)
Made in USA from North American cedar, 3/4 inch thick boards (most cedar beds on Amazon are 1/2 inch — thickness drives lifespan). 17.5 inch depth gives deep-rooted crops the room extension services recommend. Cedar is naturally rot-resistant without pressure-treatment chemicals, suitable for vegetable production.
View on AmazonVego Garden Woodgrain Series Raised Bed (4 ft x 8 ft x 16 in tall)
Vego Garden is the gardening community's premium raised bed brand, known for durable powder-coated metal construction with wood-grain aesthetics. 4 by 8 ft footprint, 16 inches tall, food-safe coating. Combines metal durability (no rot, decades of life) with the visual warmth of wood — best for gardeners who want a long-term investment.
View on AmazonGardening books
The most useful mix is three categories: a beginner guide, a reference manual for diagnosis and crop-by-crop lookup, and a soil science book. Look for region-aware editions, strong visuals, and evidence-based authorship.
Source: Purdue Extension; Master Gardener resources
Old Farmer's Almanac Vegetable Gardener's Handbook
The quick-reference classic. Step-by-step format you can keep near the garden. Trusted since 1792.
View on AmazonThe Vegetable Gardener's Bible by Ed Smith
The book extension agents recommend. Covers raised beds, organic methods, and deep soil — the comprehensive guide that turns beginners into confident growers.
View on AmazonVeg in One Bed by Huw Richards
Month-by-month raised bed guide from one of the most respected modern garden educators. Beautiful hardcover that doubles as a practical planner.
View on AmazonSources
Reference material and extension guidance used to build this growing guide.
Related Plants
More plants from the same family or type that fit naturally alongside this guide.
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