QUESTION: What is the best fertilizer for lettuce? I’ve sprayed fish emulsion on my lettuce leaves before and there was residual smell. Is there a better way to use fish emulsion, or what fertilizer is safe for lettuce? -Terri M
ANSWER: Lettuce requires the soil to be fertile and rich when seeds are sown, and your lettuce plants will also need fertilization as they grow. Because lettuces are a “cut and come again” crop, they need plenty of fertilizer to help them keep producing new leaves for the next harvest. Feed lettuce plants every two weeks with a balanced water soluble or granular fertilizer, such as a 10-10-10 or a 5-5-5, diluted to half strength. Look for a fertilizer in which the three numbers separated by hyphens are equal or almost equal. These numbers represent the percentage of nitrogen, phosphate, and potassium each fertilizer contains.
Before planting your lettuce, amend your garden soil with several inches of rich organic matter, such as aged compost,well rotted manure, fish emulsion, or another additive. (Amending your soil with compost isn’t quite the same as fertilizing plants. Get the rundown in how they’re different and when to use each in our article Compost Versus Fertilizer Explained.) The best time to prepare the soil for a spring planting season is the previous fall so the organic material has time to decompose and become part of your soil. Waiting a while to plant after amending your soil with certain fertilizers, like chicken manure or fresh manure, will also ensure your plants don’t get “burned” by the excess nitrogen in the fertilizer.