Mammoth Russian Sunflower Seeds 6140. If you want to grow the champion sunflower for the fall fair, this heirloom variety is the one to choose! Huge, single yellow blooms ranging from 25-35 cm (10-14″) in diameter are produced on tree trunk like stems that can easily grow to 3 m (9′) or more in height! This is the best variety for feeding the birds as well as for roasting seed for yourself! Taller plants may need staking due to the weight of their mighty seed heads! This product is part of the Urban Garden Collection; click here to check it out.
How to Grow
9-10 seed/gram. Easy to grow. In late May, choose a sunny site with well draining soil and sow seed about 6-12 mm (1/4-1/2″) deep and 7.5-10 cm (3-4″) apart. Thin or transplant seedlings to 30-45 cm (12-18″) apart. Seed can be started 2-3 weeks early indoors using plantable peat pots or Jiffy 7’s at 21 C (70 F). Harden off seedlings then transplant to a site in full sun. Keep plants evenly watered and fertilize twice during the season with a granular 15-5-15 or equivalent.