You are here

Fertilizing

Discover Your Garden’s Fertilizer Needs

The amount of fertilizer to apply depends on the natural fertility of the soil, amount of organic matter, type of fertilizer, and the vegetables being grown. Get a soil test to determine your garden’s fertilizer needs.

In addition to soil testing, you also must measure your garden to determine the number of square feet it occupies. Garden fertilizer recommendations are based on 1,000 square feet, and an area of 1,000 square feet could measure 25 by 40, 20 by 50, 30 by 33, or other dimensions according to your plot layout.

If your area is smaller than 1,000 square feet, divide the actual area by 1,000; then multiply the decimal figure by the recommended lime and fertilizer rates. For example, if your plot measures 16 by 24, the area contains 384 square feet; 384 divided by 1,000 equals .384; multiply .384 by your recommended fertilizer rate to determine the amount of fertilizer to apply.

Measuring Table for
Fertilizer, Weight per Pint

Superphosphate.....1 lb
Muriate of Potash.....1 lb
34-0-0.....1 lb
Nitrate of Soda.....11⁄4 lb
Limestone.....11⁄4 lb
Mixed fertilizer 6-8-8.....1 lb
Mixed fertilizer 13-13-13.....1 lb

• • •

Vegetable Tolerance
to Acid Soils

Slightly tolerant
(pH 6.8 to 6.0)

Asparagus
Beets
Broccoli
Cauliflower
Chinese Cabbage
Lettuce
Muskmelons
New Zealand Spinach
Okra
Onions
Peanuts
Spinach
Swiss Chard

Moderately tolerant
(pH 6.8 to 5.5)

Beans
Brussels Sprouts
Carrots
Collards
Corn
Cucumbers
Eggplant
English Peas
Garlic
Kale
Kohlrabi
Lima Beans
Parsley Peppers
Pumpkins
Radishes Rutabagas
Soybeans
Squash
Sunflowers
Tomatoes
Turnips

Very tolerant
(pH 6.8 to 5.0)

Irish Potatoes
Sweet Potatoes
Watermelons

Vegetable plants require many different nutrient elements for good growth and production, but nitrogen (N), phosphorus (P), and potassium (K) are the three nutrients of concern to most gardeners. Calcium (Ca) and magnesium (Mg) are supplied by limestone. The other required elements are obtained from air, water, and soil.

Mixed fertilizers are normally sold by grade and contain two or three major plant nutrients. The numbers in the grade refer to the percent nitrogen (N), available phosphate (P2O5), and available potash (K2O).

Fertilizer sources of the major plant nutrients are ammonium sulfate (21 percent nitrogen, 21-0-0), a blend of ammonium sulfate and urea (34 percent nitrogen, 34-0-0), nitrate of soda (16 percent N, 16-0-0), calcium nitrate (15.5 percent N, 15.5-0-0, 19 percent calcium), urea (46 percent N), superphosphate (46 percent P2O5, 0-46-0), and muriate of potash (60 percent K2O, 0-0-60). Because many garden soils have been heavily fertilized for years, soil test results often indicate extremely high soil levels of phosphorus and potassium. In these cases, nitrogen is the only fertilizer recommended, since additional phosphorus and potassium are unnecessary.

Where nitrogen is the only fertilizer recommended, the usual recommendation is for 3 pounds of 34-0-0 (3 pints) per 1,000 square feet of garden space prior to planting. Fertilization with unnecessary nutrients can “salt out” the garden and damage plant growth.

Vegetables differ in their fertilizer requirements. Leafy greens like mustard, turnips, collards, cabbage, and spinach are heavy users of nitrogen. Broccoli and sweet corn also require more nitrogen than some other vegetables. While nitrogen is important to the plant growth of fruit and root vegetables, phosphorus and potash are important to the proper development of roots and seeds. Peanuts, southern peas, and beans get nitrogen from the air and do not require heavy nitrogen fertilization. Overfertilizing these vegetables with nitrogen causes excessive growth of leaves at the expense of the fruit.

Apply fertilizer before or at planting. Two methods of application are “in the row” and “broadcast.” For most gardeners, the broadcast method is more practical.

To broadcast, spread the recommended amount of fertilizer evenly over the soil surface and then thoroughly mix it into the soil during soil preparation. Heavy feeding vegetables need additional fertilizer (side-dressing) after the plants are well established.

For row application, apply the recommended fertilizer to the row. Mix it thoroughly with the soil so that it will not damage the seed and tender plants.

Fertilizer can be applied in a combination of broadcast and row applications. Broadcast two-thirds of the recommended fertilizer over the entire garden surface and mix it into the soil. Apply the remaining one-third of the fertilizer in furrows 3 inches to either side of the row and slightly below the level of the seeds.

Nitrogen fertilizer applied before or at planting time usually does not supply all the nitrogen needed during the growing season for heavy- and medium-feeding vegetables. Also, irrigation and rain can leach water-soluble nutrients, especially nitrogen, into deeper areas of the soil, out of the reach of the roots of shallow-rooted vegetables.

Apply (side-dress) additional nitrogen fertilizer along the row 4 to 6 inches from the base of the plants when plants are established, being careful to keep all fertilizer off plant leaves.

Side-Dress Applications of Nitrogen

(1 pint of 34-0-0 per 100 feet of row, 31⁄3 tablespoons per 10 feet of row)

  • Beans at 3- to 4-leaf stage
  • Beets, carrots 4 to 6 weeks after planting
  • Bell peppers, eggplant, tomatoes after first fruit set and again at 4- to 6-week intervals
  • Broccoli, cabbage, cauliflower, Brussels sprouts 3 weeks after transplanting or after danger of late freeze in spring; broccoli again when heads begin to show
  • Cucumbers, muskmelons, watermelons, winter squash when vines begin to run
  • English peas when plants are 4 to 6 inches tall
  • Irish potatoes when sprouts break through soil surface
  • Leafy greens (mustard, turnips, chard, collards) when plants are about one-third grown
  • Lettuce, kohlrabi, Chinese cabbage 2 weeks after transplanting; 4 weeks after sowing seed
  • Okra after first pods are harvested
  • Onions (green and bulb)—from sets when tops are 6 inches high —from transplants when established and actively growing
  • Peanuts none
  • Radishes none
  • Southern peas none
  • Summer squash before bloom when plants are 8 to 10 inches tall and again in 4 weeks
  • Sweet corn when 8 inches high and again when knee high
  • Sweet potatoes none
  • Turnips (roots), rutabagas 4 weeks after sowing seeds
  • Tomatoes when first fruit are 1 inch in diameter; again at first harvest
Print Friendly, PDF & Email

Publications

News

Yellow squash in a paper bowl sitting on a red and white checkered tablecloth.
Filed Under: Fruit, Farmers Markets, Vegetable Gardens June 4, 2019

When you visit your community farmers market, you know you're purchasing local produce in its peak season. Fruits and vegetables have more flavor and are typically less expensive when they’re in season. So, when you go to the farmers market, how do you make the most out of in-season produce? (Photo by Michaela Parker)

Tiny brown insects scattered across the underside of a green eggplant leaf.
Filed Under: Lawn and Garden, Vegetable Gardens May 31, 2019

No matter how you slice it, gardening is a risky business.

We have no control over the weather, waves of pestilence, the threat of plant diseases. It’s a wonder we don’t all just chuck our gardening tools and say, “See you at the farmers market.”

Multiple clusters of blueberries in varying stages of ripeness adorn a branch covered with green leaves.
Filed Under: Lawn and Garden, Flower Gardens, Herb Gardens, Trees, Vegetable Gardens May 28, 2019

If edibles are on your list for the landscape or garden this year, check out the list of Mississippi Medallion winners. They are proven performers when it comes to our Mississippi climate.

Our horticulture experts help select several plants, including fruits and vegetables, each year that make the cut. 

Two red and orange marigolds in focus with several yellow, red and orange marigolds out of focus in the background.
Filed Under: Lawn and Garden, Flower Gardens, Vegetable Gardens May 21, 2019

I love riding around town looking at everyone’s front yard landscapes. I know how much work goes into making it look top-notch! A lot has been done, but there’s plenty more to do in your yard and garden.

Several small and compact violet flowers on long stems with green foliage.
Filed Under: Lawn and Garden, Flower Gardens, Herb Gardens, Trees, Vegetable Gardens May 7, 2019

Do you want surefire performance in your landscape and vegetable garden, but don’t know what to look for when you go to the garden center?

Watch

Okra
Southern Gardening

Okra

Sunday, November 4, 2018 - 2:00am
Sharpening Your Tools
Southern Gardening

Sharpening Your Tools

Sunday, March 11, 2018 - 5:00am
Tomato Tips  - MSU Extension Service
Extension Stories

Tomato Tips

Tuesday, April 25, 2017 - 3:00pm
Winter Gardens
Southern Gardening

Winter Gardens

Saturday, January 16, 2016 - 6:00pm

Listen

Monday, December 17, 2018 - 7:00am
Friday, October 26, 2018 - 2:00am
Wednesday, October 17, 2018 - 2:00am
Friday, October 5, 2018 - 2:00am
Thursday, October 4, 2018 - 2:00am

Contact Your County Office

Upcoming Events

Your Extension Experts

Extension/Research Professor
Greenhouse Tomatoes and other vegetables, Field Vegetables, Mushrooms