Spinach must have at least 6 weeks of cool weather from seeding to harvest.
Plant seeds outdoors 4 to 6 weeks before your last spring frost date, and again 4 to 6 weeks before the first fall frost date.
Spinach bolts when days are 14 to 16 hours long; warm weather makes it bolt even faster.
Mix compost, manure, and/or fertilizer into each row or plot before planting.
Sow seeds 1/2 inch deep, about 12 seeds per foot of row, or sprinkle them over a wide row or bed.
When seedlings are 1 inch tall, thin to stand 4 inches apart.
Water every few days during dry spells; mulch spinach planted in rows to retain soil moisture.
See our article Summer's Bad Guys by Charlie Nardozzi for controls of common spinach pests such as leaf miners and aphids.
To harvest early, cut individual leaves as soon as they are big enough to eat. When the weather warms up, cut the whole plant close to the ground, below the lowest leaf. Harvest again after a few new leaves reappear. Repeat as necessary.