Liquid fertilizers provide needed plant nutrients for plants in pots or in your garden. Liquid fertilizers release their nutrients faster than organic dry fertilizers, so plants suffering from nutrient deficiencies can receive the nutrients they need immediately. Organic liquid plant fertilizers are easy to use and easy to make, or purchase synthetic liquid fertilizers.
Compost Tea and Worm Compost Tea
Compost tea or worm compost tea are both excellent liquid fertilizers that are high in nitrogen and other nutrients that plants need. Both are made by seeping the solid compost or worm castings in water, with stirring for aeration, for several days.
Worm castings are especially rich and make a concentrated tea that is high in nitrogen, which should be diluted 1/4 cup for every gallon of non-chlorinated water. Use the resulting liquid to start new seedlings or to give plants a boost throughout the season.
Fish emulsion is high in potassium and contains many micronutrients and trace elements that plants need. A foliar spray of fish emulsion mixed with water can be applied directly onto plant leaves for a quick boost. Purchase in concentrated form organically, or with synthetic additives.
Kelp Meal Tea
Kelp, or seaweed, activates microbes in soil to help break down organic matter, which makes nutrients available to plants. It also contains macro- and micro-organisms and trace elements that help plants grow and thrive. Stir kelp meal into a gallon of water to make a liquid tea. Kelp meal tea can be used to water plants or as a foliar spray to pep up stressed plants.
Purchasing Liquid Fertilizers
When shopping for a liquid fertilizer, read the package to identify which nutrients plants will receive from the product. Many packages will have three numbers on the label, such as 10-20-10. These numbers indicate the ratio of the three main nutrients that plants need (nitrogen/phosphorus/potassium), although secondary nutrients, minerals and trace elements are also required.
A liquid fertilizer that contains all three of these nutrients (regardless of the ratios) is considered to be a good general fertilizer, while liquid fertilizers with higher content of one over the others may be required for plants with a deficiency of that particular nutrient.
Identifying Needed Nutrients
Knowing which nutrients a plant needs can help in determining which liquid fertilizer is needed. To identify which nutrients plants may be lacking look for signs on the plants themselves. When the green color of older leaves fade and turn yellow, but younger leaves appear unaffected, it is an indication of a nitrogen deficiency.
A phosphorous deficiency is indicated by purplish or bronze colored leaves. A lack of potassium might be suspected if leaves have yellow, translucent spots and browning leaf margins.