Vegetable Gardening Tips: Soil and Fertilizer

Soil Testing

• To ensure you apply the appropriate amount of fertilizer conduct a soil test first. Take a sample of the soil from the garden and analyze it to determine the nutrient levels available for your growing vegetables. You can find test kits available at some seed stores, through colleges with an agricultural department and online. With these kits, you either mail or drop off your sample. Use the results to determine what nutrients to add to the soil to make it healthy for your vegetable garden.

Nutrient Mixture

• Your soil needs to contain sufficient levels of nitrogen, phosphorus and potassium in order to grow healthy vegetables. Nitrogen amounts should be higher than 50 parts per million, phosphorus should be more than 14 ppm, and potassium levels need to be at least 181 ppm, according to the Colorado State University Extension. When you choose fertilizer, look at the analysis listed on the package. The three numbers represent the percentage of nitrogen, phosphate, and potash found in the fertilizer. With the last two, you need to use math to find out the actual amounts of phosphorus and potassium. Multiply the second number by 0.43 to determine the phosphorus content; multiply the third number by 0.83 to determine the potassium content.

Organic or Synthetic Fertilizer

• Synthetic fertilizers provide fast access to nutrients so your vegetables can begin benefiting from them quickly. Organic fertilizers work slower but provide long term improvement to the structure of the soil. Some synthetic fertilizers also pose a threat to earthworms. Organic products also contain additional micronutrients plants need. These micronutrients, such as magnesium and sulfur, need to be added if you use synthetic fertilizers. If you use manure as your organic fertilizer, apply it at least 120 days before harvesting the vegetables to reduce the risk of bacterial contamination.

Soil pH

• Vegetables gardens grow best in soil with a pH level between 6 and 7. If the level is lower, the soil is too acidic. If the level is higher, the soil is too alkaline. At either pH extreme, plants are unable to use some nutrients because they cannot be released by the soil, or can be so readily available they reach toxic levels for vegetables. You can add lime to your soil in order to balance out the pH levels.