Planting Timeline
Showing dates for Black Krim in USDA Zone 7
All Zone 7 tomato →Zone Map
Click a state to update dates
Black Krim · Zones 3–11
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | March – April | June – June | — | August – September |
| Zone 4 | March – March | May – June | — | August – September |
| Zone 5 | February – March | May – June | — | July – October |
| Zone 6 | February – March | May – May | — | July – October |
| Zone 7 | February – March | April – May | — | July – October |
| Zone 8 | January – March | April – May | — | June – November |
| Zone 9 | December – March | March – May | — | June – November |
| Zone 10 | November – March | March – April | — | May – December |
Complete Growing Guide
Growing Black Krim tomatoes successfully starts with proper site preparation. Choose your sunniest garden spot and amend the soil with 2-3 inches of compost and a balanced organic fertilizer (10-10-10) worked 8-10 inches deep. The soil pH should ideally sit between 6.0-6.8 for optimal nutrient uptake.
Start your Black Krim seeds indoors 6-8 weeks before your last expected frost date. Plant seeds ¼ inch deep in quality seed starting mix, maintaining soil temperature around 70-75°F. You'll see germination in 5-10 days. Once seedlings develop their first true leaves, transplant to 4-inch pots and begin weekly feeding with diluted liquid fertilizer.
Transplanting requires patience with this Russian heirloom. Wait until nighttime temperatures consistently stay above 50°F and soil reaches 65°F – typically 2-3 weeks after your last frost. Cold soil stunts Black Krim growth more than other varieties. Harden off seedlings for 7-10 days, gradually increasing outdoor exposure.
Space plants 24-30 inches apart in rows 3 feet wide. Install sturdy 6-foot stakes or cages immediately – Black Krim produces heavy fruit on vigorous, indeterminate plants reaching 6-8 feet tall. The weight of mature tomatoes will snap unsupported branches.
Fertilize every 3-4 weeks with lower nitrogen fertilizer once flowering begins (5-10-10 works well). Too much nitrogen delays fruit development and increases disease susceptibility. Apply 1-2 inches of organic mulch around plants, keeping it 3 inches from stems to prevent fungal issues.
Consistent watering prevents the cracking that plagues this variety. Provide 1-1.5 inches weekly through drip irrigation or soaker hoses. Overhead watering invites disease problems that Black Krim is particularly susceptible to. Water deeply but less frequently to encourage deep root development.
Prune suckers regularly and remove lower leaves touching the ground. Improve air circulation by selectively removing interior branches, especially important in humid climates where late blight thrives. In zones 3-5, consider growing in high tunnels or large containers that can be moved for season extension.
Harvesting
Black Krim tomatoes signal ripeness through subtle color changes that differ from typical red varieties. Look for the signature dark purple-black coloration with distinctive green shoulders – these green areas remain even when fully ripe, which confuses many first-time growers. The purple-black color should appear rich and deep, not dull or grayish.
Test ripeness by gentle pressure – ripe Black Krims yield slightly to thumb pressure while maintaining firmness. The bottom (blossom end) develops a slight give before the shoulders soften. Harvest in early morning when temperatures are cool and fruit is fully hydrated from overnight moisture.
Use the 'twist and pull' method, supporting the vine while gently twisting the fruit. Properly ripe Black Krims release easily from the stem. If you encounter resistance, wait another day or two. Alternatively, cut the stem with clean pruners, leaving a short stub to prevent tearing the fruit skin.
Harvest Black Krims at the first sign of color change if heavy rains are predicted – this variety's thin skin makes it extremely prone to cracking. Green-harvested fruits will continue ripening indoors on a sunny windowsill, though flavor won't be as complex as vine-ripened tomatoes.
Storage & Preservation
Store fresh Black Krim tomatoes stem-side down at room temperature away from direct sunlight. Never refrigerate unless fully ripe and you need to extend life by 2-3 days – cold temperatures destroy the complex flavor compounds that make this variety special. Properly stored Black Krims maintain peak flavor for 5-7 days, longer than many thin-skinned heirlooms.
For preservation, Black Krim's low acidity makes it unsuitable for traditional water bath canning unless you add lemon juice or citric acid. However, the rich flavor excels in frozen applications. Core and quarter ripe tomatoes, then freeze in portions for winter sauces and soups. The texture won't work for fresh use after freezing, but the smoky flavor intensifies beautifully in cooked dishes.
Dehydrating works exceptionally well with Black Krims. Slice ¼ inch thick, lightly salt, and dehydrate at 135°F for 8-12 hours. The concentrated flavor rivals expensive sun-dried tomatoes and stores for months in airtight containers.
History & Origin
Black Krim originates from the Isle of Krim (now Crimea) in the Black Sea, where it was grown by local gardeners for generations before reaching Western gardens in the 1990s. The variety's name literally translates to 'Black Crimea,' referencing both its distinctive dark coloration and geographic origin.
This heirloom was likely developed through generations of seed saving by Crimean farmers who selected for the darkest, most flavorful fruits. The region's maritime climate and rich soils contributed to the variety's characteristic complex flavor profile and stunning appearance.
Lars Rosenberg, a Swedish gardener, is credited with introducing Black Krim to Western Europe in the early 1990s, though the exact pathway remains somewhat mysterious. American seed companies began offering it in the mid-1990s, where it quickly gained popularity among heirloom enthusiasts and gourmet gardeners.
The variety represents the rich tradition of Soviet-era home gardening, where families maintained private plots and carefully saved seeds from their best performers. This careful selection over decades created the exceptional flavor complexity that makes Black Krim a standout among dark tomato varieties today.
Advantages
- +Exceptional complex flavor with unique smoky undertones and mild saltiness that's unmatched among dark tomatoes
- +Stunning visual appeal with deep purple-black skin and green shoulders creates dramatic contrast in dishes
- +Medium-large fruit size (6-12 oz) perfect for gourmet slicing and sandwich applications
- +Strong indeterminate growth produces abundant harvests throughout the season until frost
- +Heat tolerance superior to many other dark heirloom varieties, performing well in southern gardens
- +Low acidity makes it digestible for people sensitive to high-acid tomatoes
- +Open-pollinated variety allows for seed saving and maintaining genetic diversity
Considerations
- -Extremely prone to fruit cracking during periods of inconsistent moisture or heavy rain
- -Thin skin makes fruits susceptible to splitting and reduces shipping/storage life
- -Typical heirloom disease susceptibility, particularly vulnerable to late blight in humid conditions
- -Requires consistent deep watering schedule – drought stress immediately affects fruit quality
- -Low acid content makes water bath canning unsafe without added acid
Companion Plants
Plant Together
Basil
Repels aphids and whiteflies, may improve tomato flavor
Marigold
Deters nematodes and aphids with natural compounds
Oregano
Repels spider mites and provides ground cover
Parsley
Attracts beneficial insects like hoverflies and parasitic wasps
Carrots
Help break up soil and don't compete for nutrients
Nasturtium
Acts as trap crop for aphids and cucumber beetles
Chives
Repels aphids and may improve disease resistance
Lettuce
Provides living mulch and utilizes different soil layers
Keep Apart
Black Walnut
Releases juglone toxin that causes tomato wilt and stunting
Fennel
Inhibits growth through allelopathic compounds
Brassicas
Compete for similar nutrients and may stunt tomato growth
Corn
Both attract corn earworm which also damages tomatoes
Pests & Disease Resistance
Resistance
Typical heirloom susceptibility, prone to cracking in wet conditions
Common Pests
Tomato hornworm, aphids, whiteflies, spider mites
Diseases
Late blight, early blight, blossom end rot, fruit cracking