Cool-season Spinach

• Cool-season spinach grows well when days are less than 14 hours long and temperatures do not reach 80 degrees. In Ohio, cool-season spinach should be sown directly into soil in October to mid-November for a harvest six weeks later. Cool-season seeds can be planted directly in the soil in early April for a spring harvest, but they will bolt when temperatures rise above 60 degrees.
  
  

Warm-season Spinach

• Warm-season spinach should be started six weeks before last frost, usually in early March in Ohio. Start seeds indoors in light soil and water as needed before replanting the sprouts outdoors. There are several times to plant spinach throughout spring and summer. For a fall harvest, plant in midsummer.
  
  

Planting and Disease

• Plant spinach in three-week intervals to allow for a longer harvesting time. Work soil 10 inches deep, adding rich organic materials. Plant seeds one-half inch deep and 2 inches apart. Watch for signs of germination and water regularly. Spinach grown in Ohio is susceptible to rust and mildew because of the humid climate. To help prevent these diseases, treat soil with fertilizer approved for vegetable gardens.
  
  

Growing and Harvesting

• Thin out weaker plants as they emerge. Spinach is mature in 30 to 50 days from sowing seeds. To harvest the spinach, pinch off leaves as needed. Leave the central rosette intact. When spinach begins to grow a central stem, uproot the plant to prevent it from spreading seeds.