Culture: Very hardy, spinach prefers cool temperatures. Planted as soon as the ground can be worked in spring to avoid early bolting. Minimum germination temperature 35°, optimal range 45–65°. Spinach seed will not germinate in soil temperatures above 85°. For fall crop try late July–Aug. sowing; to overwinter, sow late Aug.–Sept. Heavy nitrogen requirements, but avoid applying high-nitrogen fertilizers shortly before harvest to prevent high nitrate levels in the leaves.
Pick large leaves often for heavier production. Smooth-leaved spinach is easier to wash than the semi-savoyed type and is increasingly preferred. Heat, crowding and long day-length (over 14 hours) trigger premature bolting. To retard bolting, avoid hot-weather planting, use wider spacing and irrigate or use shade cloth.
The use of disease-resistant and hardy varieties, cold frames, row covers and hoophouses has made spinach into a nearly year-round crop. Growers should rely on Space or Oceanside for winter production.
See also New Zealand Spinach and Caucasian Mountain Spinach.
Downy Mildew (DM)
- BM: Blue Mold
- CLS: Cladosporium Leaf Spot
- CMV: Cucumber Mosaic Virus
- DM: Downy Mildew
is caused in spinach by Peronospora farinosa
f. sp. spinaciae
. This pathogen evolves new races at a fast clip, challenging breeders and growers worldwide to keep up. Resistant varieties are the main management tool. While formerly considered Somebody Else’s Problem, spinach DM has popped up here and there in the Northeast on a seemingly random cross section of spinach varieties. Most cases have been in protected winter crops. Researchers such as Dr. Meg McGrath of Cornell, along with regional seed companies, are tracking these occurrences with hopes of more knowledge before it becomes a major problem. Stay tuned! Until then, good info and visual spinach-disease primers can be found here
For the latest results of our germination tests, please see the germination page.