How to feed plants

Well-fed plants grow fast and large, shading out weeds and usually staying disease-free. But shopping for the right plant food at the nursery can be confusing; specialty fertilizers for camellias, lawns, roses, tomatoes, and other plants crowd shelves alongside all-purpose fertilizers and organic products. Most plant foods come in a wide variety of forms: liquids, granules, pellets, tablets, and stakes. Which is the best choice for your lawn? For blooms? And what do all those numbers on the labels mean? For answers, see our fertilizer guide below.

Fortunately, fertilizers fall into three main categories: granular, liquid, and controlled release. Most contain three primary nutrients ― nitrogen (N), phosphorus (P), and potassium (K) ― and a variety of micronutrients, including iron and manganese. Nitrogen is usually the most important and, for a given price, the better value. It promotes green growth, so lawns need a lot of it (29-3-4 is a common turf formula).

Phosphorus helps rooting and speeds up flowering and fruiting, so a high-phosphorus fertilizer such as 5-10-10 is favored for flowers and vegetables. Potassium fuels plant metabolism and root development, and it increases the size and quality of fruits and nuts; most balanced fertilizers contain a sufficient amount.

Fertilizer labels indicate the percentage of each primary nutrient ― nitrogen (N), phosphorus (P), and potassium (K) ― in a three-number sequence, such as 12-4-8. The first number shows the percentage of nitrogen; the second, phosphorus; the third, potassium.

FERTILIZER GUIDE

Here are four easy-to-use types and how to apply them. No matter which type you choose, feed plants regularly during the growing season, and they'll reward you with lush growth.

Granular
The least expensive plant foods, these usually last a month or two and need to be reapplied. Standard for lawns and general garden feeding.
To apply. Broadcast or spread over lawns; sprinkle onto the soil in flower beds, then scratch, rake, or dig it in. Mix into well-tilled soil before planting vegetables, or apply along both sides of an existing row and mix it into top few inches of soil. Soak the soil thoroughly after each application.

Liquid
Includes concentrates to dilute in water, and dry products that dissolve in water. They're immediately taken up through leaves and roots. Effective for container plants.
To apply. Follow label directions for dilution to avoid burning plants. Apply close to plant roots with a watering can or an injecting device on a hose every week or two.

Controlled release
Beadlike granules release nutrients into the soil over several months; longevity depends on formulation. Apply it once or twice a year (some products feed for three to four months, others for eight to nine months). But you pay extra for the convenience.
To apply. Dig into the soil at planting time or scratch into the soil surface. Feeds a broad range of plants, from annuals and perennials to ornamentals in containers.

Organic
Natural-based products usually sold in boxes. Bat guano (8-5-1.5) and fish pellets (8-5-1) contain all three primary nutrients. For nitrogen (to green up ornamentals in spring), try blood meal, cottonseed meal, or poultry waste; for phosphorus (to boost bloom), bone meal; for potassium, kelp or granite meal.
To apply. Scatter the food above plant roots, work into soil, and water well.