October 27, 2007
Plant of the Week
Spinach is a cool-season crop that when planted by seed germinates very poorly, if at all, in hot soils. Therefore, to avoid a poor stand, the first planting should occur when soil temperatures are 85º F. or below. Many gardeners have had bad luck growing spinach by seed because they ignored this growing requirement. Gardeners plant fall gardens in August and September and are actually harvesting fall produce before spinach planting should even be considered. Gardeners are out of the planting mood when optimum spinach planting time arrives. They are discouraged by the zero success of earlier spinach planting attempts, so they bypass the opportunity of planting the most nutritious, Texas-salad vegetable–spinach.
However, an easy-to-grow spinach transplant is now available in local nurseries. It’s the Texas A&M recommended disease-resistant variety named ‘Coho.’ Spinach varieties are available in flat-leaved, semi-crinkle-leaved (semi-Savoy), and crinkle-leaved (Savoy) types. The flat-leaved types are preferred for canning and the crinkle-leaved types are best for fresh use. Because of the fungus diseases that damage spinach growth and leaf appearance, only certain varieties are recommended. The disease resistant variety that is now available is ‘Coho.’ This semi-Savoy variety performs best if transplanted between October 15th and January 1st.
Spinach transplants should be planted in rows on top of raised planting beds. Planting in rows is preferable since weeds that emerge near the spinach plants can be more easily removed. Transplants should be spaced four-to-six inches apart. Because most people will want a continuous supply of garden-fresh spinach salad, many transplants will be required. To save some money on the purchase of transplants, shop around for a cooperative nurseryman who will sell transplants cheaper if you buy in quantity or buy a flat of 96 transplants. For all of you, non-gardening types, plan to transplant some spinach into a sunny flowerbed or patio container, so you too can eat yourself to health. Spinach will tolerate and produce in a partially shaded planting location, and produce a fair crop with less than full sunlight.
Gardeners have struggled with trying to grow spinach plants successfully. Planting seed during adverse growing conditions accounts for the main problem, but hungry pillbugs (sowbugs), snails, and soil fungus have also killed a lot of spinach seedlings. An obvious answer is a larger, tougher seedling in the form of a transplant. Tough-stemmed transplants are more resistant to damping off fungus that causes stem rotting. Where soil fungus damage has been a problem use dusting sulfur in the planting furrow and on the soil surface around the plant. Pillbugs (sowbugs) and snails should be eradicated, even if transplants are used, by applying garden-approved baits at planting time and applying for several weeks (seven-to-ten day intervals) thereafter.
About two weeks after transplanting, you should stimulate the growth of the spinach with a light application of a high slow-release nitrogen fertilizer. Use about one pound of 19-5-9 analysis fertilizer for each 30-foot row of planted spinach. Apply the fertilizer to the soil near the side of the plants and then water it in thoroughly.
Depending upon the weather, harvesting of spinach begins approximately six-to-eight weeks after planting. You’ll note that as the weather cools down your spinach will take a little longer to fully mature and will grow more upright. Generally, spinach that matures when temperatures average between 50º and 60º F. will be fuller-bodied with thicker, tenderer leaves.
Periodic harvesting can occur by removing the older, outer leaves, thus assuring a continuous supply and stimulating the plants to initiate more leaves. A mass-harvest method that works quite well is to harvest all spinach plant foliage above the crown with a sharp knife, leaving the crown or growing point of the plant and roots in place so that a second crop can be produced by the same plant. A light application of 19-5-9 fertilizer and watering should follow this type of harvest to encourage new leaf growth.
NOW IS the month to plant the most nutritious garden vegetable–spinach. And now that you have the right transplant and know how to assure spinach growing success, the fault of malnutrition is yours only if you don’t plant this most healthful of the vegetable crops.
Nutritionally speaking, spinach is a super-champ of the vegetable garden. Spinach has twice as much protein, calcium, iron, potassium, Vitamin A, Vitamin B, and B-2, niacin and Vitamin C as any other of the leafy greens.
Remember, Learn and Have Fun!
David Rodriguez is County Extension Agent-Horticulture, Bexar County. For more information, call the Master Gardener ‘Hotline’ at (210) 467-6575 or visit our County Extension website at https://bexar-tx.tamu.edu, click under Horticulture and Gardening.