Solanum lycopersicum 'Black Plum' is a Russian heirloom paste tomato variety acquired by Seed Savers Exchange from Marina Danilenko of Moscow in the early 1990s. This indeterminate variety produces distinctive deep mahogany to black-red, plum-shaped fruits that are excellent for sauces, pastes, and canning. Seeds germinate readily within 5-14 days when provided with warm, consistently moist conditions and do not require light for germination.
Before sowing
No pre-treatment needed — sow directly.
Sowing
What to expect
Tips
Maintain warm soil (70-85°F/21-29°C) using a bottom heat mat for optimal and rapid germination. Keep soil consistently moist but not waterlogged during germination; use a humidity dome to retain moisture and reduce watering frequency. Sow seeds in sterile, well-draining seed-starting mix at ¼ inch deep (approximately 6mm); cover lightly and press gently for good seed-to-soil contact. Once seedlings emerge, remove the humidity dome immediately and provide bright light (14-16 hours daily) under grow lights to prevent leggy growth. Avoid waterlogged conditions as they promote fungal diseases like damping off. Once seedlings develop their first true leaves, pot up into larger containers (3-4 inches), burying stems up to the lowest leaves to promote strong root development. Start seeds indoors 6-8 weeks before the last frost date. Transplant outdoors only after night temperatures consistently exceed 55-65°F and after gradual hardening off over 1-2 weeks. This hardy variety adapts well to diverse climates and performs especially well in cooler summer regions.
Sources: Tradewinds Fruit, Easyseeds, Greg.app, Two Seeds in a Pod, Restoration Seeds, PlotMyGarden, Tim's Tomatoes, Specialty Produce, Plantura, Ujamaa Seeds, Seed Savers Exchange
