By Linda Morrison
“Pre-sprouting spinach seeds in late summer is very worthwhile. For this we do the whole sprouting process in the fridge, and I confess we don’t rinse them at all! One week is a good length of time for fridge sprouting of spinach.”
Pam Dawling, author of ‘The Year-Round Hoophouse’
A few weeks ago, I planted three types of salad greens for a late summer crop. I planted “by the moon” during the New Moon, or first quarter phase, and was extremely pleased when two of them sprouted in just 3-5 days. The spinach, on the other hand, barely sprouted at all and when the baby turkeys laid on them, those few disappeared. Then I read author Pam Dawling’s articles on starting seeds in hot weather. She quoted Nancy Bubel’s New Seed Starter’s Handbook: the optimum temperature for germinating spinach is between 40 and 75 degrees F. At 59 degrees F spinach will produce 82% normal seedlings, at 68 degrees F, down to 52%, and a very low 28% at 77 degrees F. I grabbed my compost thermometer and poked it into the raised bed and checked on the temperature throughout the day. Early in the morning it was in the 70s and as the day heated up to 96 degrees, it was 93 a couple inches down into the soil. Wow! We gardeners learn something new every day.
Because spinach is an excellent cool weather crop, I still want to plant it soon. Dawling recommended several strategies for sprouting spinach seeds in hot weather.
1. Consider planting another crop instead. Swiss chard germinates best at 85 degrees F. Lettuce must be lower than 80 degrees F.
2. Wait until the temperatures drop for spinach. Remember, you want to be close to 59 degrees F for the best success.
3. If your soil is close to the ideal temperature, sow in the evening. After sowing, put ice on top of the soil covering the seeds. Cover with shade cloth or similar fabric. Be sure it is something the air can flow through. Keep the soil cool and moist by watering with cool water or ice several times a day until the seeds germinate. Watering should be shallow and frequent until the seedlings emerge.
4. Chilling lettuce or spinach seed can help with germination in hot weather. Place spinach seed in a double Ziploc bag and put in the freezer for two weeks before late summer sowing.
5. Pre-sprout seeds indoors in a mason jar with a special plastic draining lid (for growing sprouts to eat). Rinse twice a day, draining off the water. Sprout the seeds just until you can see they have germinated. Lettuce may be ready to plant in a day. Spinach may be done in the fridge, with the jar lying on its side. You may not even need to rinse the seeds. Give them a quarter-turn each day to tumble the seeds and even out the moisture. Allow a week for the spinach fridge sprouting. Plant in the soil in the cool of the evening and use some of the above mentioned methods to keep the seedlings cool and moist. This last idea sounds worth trying!