Lettuce Root Growth Nutrients

Soil Test

• Before you add nutrients to soil, especially for fast-growing crops, it's wise to have the soil tested first. At the very least, use a simple pH tester to make sure the acid range is suitable for growing lettuce. If you add fertilizer to soil that is too alkaline, the plant cannot absorb the minerals and they will wash away with the next heavy rain. Soils with a pH range between 6 and 6.7 are perfect for growing lettuce.

Organic Compost

• Lettuce plants are mostly water. Growing plants need ready access to water at all times, which means the moisture-holding capability of the soil must be high. Organic materials such as what you would find in well-rotted compost hold onto water and keep the surface of the soil damp much longer than soils without it. Lettuce is a shallow-rooted plant and so although you might work compost deep into the garden soil before planting, make sure there is plenty of plant material in the top six inches of the soil.

Nitrogen

• Nitrogen is necessary for leaf formation. Just as all living organisms depend on protein to support life, plants depend on the nitrogen found in the protein. Without nitrogen, the roots will be sparse, long and spindly. As a result, the leaves of the lettuce plant will be spindly and yellowed.

Phosphorus

• Phosphorus is necessary for plant metabolism. This involves photosynthesis as well as absorption of nutrients in the soil. Without phosphorus, growth slows and the roots of the plants stay small, starving the plant of the water-borne nutrients necessary for life.

Potassium

• Potassium is not a component of a plants cellular makeup, but it is present in the plants. This mineral although very abundant in the earth's crust, tends to be bound in the rocks or clay and only slowly dissolves over time. Without enough potassium, the lettuce plant's roots will be stunted and the plant unhealthy.

Calcium

• Gardeners often overlook calcium while fertilizing their garden soils. However, it is an important part of leafy plants, increasing their ability to grow. Plants low in calcium have stunted growth points, both on the roots and on the leaves.