Know Your Soil
Before applying fertilizer, it is always a good idea to take a soil test. Soil composition and nutrient content vary from one yard to the next. A soil test provides a snapshot of the nutrients available to plants in your plot. The information will help prevent overfertilization—a costly environmental hazard that is easily avoided.
Available from online sources and possibly your local Extension Service, soil test kits involve sending a sample of your soil into a testing lab. The lab analyzes the soil based on what you plan to grow. Reputable testing labs send a detailed soil nutrient report that includes fertilizer recommendations for the plants you intend to grow on the site.
Vegetable Plants
Tomatoes, peppers, beans, and other fast-groiwng annual edible plants demand a steady supply of nutrients to fuel strong spring growth. The leaf, stem, and root structures formed in spring will support robust fruit development in summer. Fertilizer in spring yields veggies in summer.
How to fertilize: An all-purpose garden fertilizer, such as 10-10-10, is best for a veggie garden. Spread 1 to 2 pounds of fertilizer per 100 square feet of planting space in spring. Mix the fertilizer into the top 4 to 6 inches of soil.
Cane Fruits
Raspberries and blackberries fruit more productively with an annual application of fertilizer in spring. For easiest application, fertilize after pruning away the dead, thorny canes from the previous season.
How to fertilize: Before growth begins in spring, spread 4 to 5 pounds of a balanced garden fertilizer, such as 10-10-10, over 100 feet of row. Uniformly broadcast the fertilizer in a 2-foot-wide band alongside plants. Don't fertilize raspberries in late spring or summer; it will cause vigorous leafy growth at the expense of fruit.
Blueberries
Soil pH influences blueberry fruit production. Fertilize plants with ammonium sulfate in spring to deliver nutrients and promote the acidic soil conditions blueberries thrive in.
How to fertilize: In early spring before leaves emerge, spread 1/2 to 1 pound of ammonium sulfate per 100 square feet of garden area. Apply the material in broad bands around plants.
Container Gardens
Limited soil volume combined with vigorous growth from spring through fall means nutrients are in high demand in container gardens. Keep container plants blooming all season with the addition of slow-release fertilizer at planting.
How to fertilize: Mix slow-release fertilizer pellets into the potting soil prior to planting. Follow fertilizer package directions exactly. Too much fertilizer can cause leafy growth and limited flowering. Some potting mixes include slow-release fertilizer; do not add more at planting time if the mix already includes it.
Roses
Specialized granular rose fertilizer makes easy work of supplying nutrients to shrub roses in early spring. Find rose fertilizer at your local garden center.
How to fertilize: After pruning roses in early spring, spread a granular rose fertilizer around the base of plants. If there is a chance that the ground is still frozen after pruning, wait to fertilize until after the ground thaws.
Perennial Edibles
Rhubarb and asparagus are such easy-care, long-lived edibles that their nutrient needs are often overlooked. Boost the nutrient availability to these productive edibles with fertilizer in early spring. They'll reward you with prolific production.
How to fertilize: In early spring before the spears or stems emerge, spread about 1 pound of a balanced garden fertilizer, such as 10-10-10, over 100 square feet of garden area.
Compost from your homemade pile or purchased is loaded with nutrients ready for plants to absorb. Applying a 1-inch-thick layer of compost over garden beds annually can often eliminate the need for any additional fertilizer.
What to Avoid Fertilizing in Spring
Some types of plants either don't benefit from fertilizer in the spring, or the additional nutrients early in the season could be detrimental. Don't apply fertilizer to the following plants:
Strawberries: Fertilizing June-bearing strawberries in spring results in lots of leafy growth, disease problems, and mushy berries. Fertilize June-bearing strawberries after the last fruit harvest in early summer. Everbearing and day-neutral strawberries can be fertilized in early spring and again in early August.
Lawns: Fertilizing a lawn in early spring causes a big flush of green, lush growth at the expense of root development. The lawn then goes into summer with a weak root system that is challenged to support it during heat and drought. Fertilize turf when it is actively growing in late spring or early summer.
Trees and Shrubs: Thriving trees and shrubs rarely need additional fertilizer. These hardy, resourceful plants generally mine all the nutrients they need from the soil. Boost nutrient availability by spreading a thin layer of compost over the root system; as the compost decomposes, nutrients will leach into the soil.
Perennials: Like healthy trees and shrubs, perennials rarely need fertilizer. Their nutrient needs are generally low and supplied by the surrounding soil. Topdressing the soil with a 1-inch-thick layer of compost annually is an excellent way to supply nutrients to perennials.
