phosphateWhen it comes to adding nutrients to your garden soil, or coddling particular plants with special needs, there are many organic options. Cultural practices such as cover cropping, crop rotation, and composting will ensure balanced nutrition of your soil in the long run, and organic amendments along the way will help your garden thrive. Here are some tips and products for success.

Before feeding your garden, always observe your plants. In fertile soil, plants may not require additional fertilizer. Do plants look lame, or require multiple smaller doses of fertilizer? (Onions like this treatment). Do your plants have poor color? Poor vigor?

Consider fertilization methods. Match options to the desired result, as some methods allow for quicker uptake. Your options are

  • Foliar feeding—spraying a liquid fertilizer on the plant leaves (Uptake is fast),
  • Soil Drenching—soaking the soil surrounding the plant with a liquid fertilizer, or
  • Side Dressing—distributing granular organic fertilizer at the base of the plants, near the stems. (Allows for slow release and plant intake of nutrients).

Learn which plants are heavy-feeders, and which ones are not. Heavy-feeders are plants that require a lot of mineral nutrients to thrive. Examples include tomatoes, cabbage, broccoli, sunflowers, and onions. Light-feeders are plants that either require very small amounts of mineral nutrients, or they themselves create nutrients. Examples include beans, peas, and lettuce.

Always use cultural methods for building soil structure and nutrition, such as crop rotation, (which can allow you to alternate heavy and light feeding crops), cover cropping with both legume (nitrogen-fixing) and grain (for organic matter) species, mulching, and composting.

Test your soil annually to learn what macronutrients your soil needs. For a closer look at soil testing, check out Ask Ruth from November 2010.

Remember, don’t waste fertilizer and time on plants that are past their prime. The best time to feed is when plants are young, or just about to set flowers and fruit. For perennial plants, there will be a recommended schedule for pruning and fertilizing in favor of optimum growth.

When adding compost to boost nutrition, consider that

  • Basic compost generally has a nutrient profile of 3-1-2 (click here to read about basic plant nutrients and how to read a nutrient breakdown)
  • Vermicompost is usually 3-1-1 or a bit higher
  • Compost and vermicompost add physical soil stuff to your garden, so consider how they affect soil. Organic matter contributes to greater acidity overtime, so while compost is balanced for garden use, you’ll want to make sure that as you’re growing your soil to promote organic matter, you’ll want to continually test the soil pH to ensure it promotes plant growth.

To boost specific mineral nutrients, here are some organic options:

NPK chart

To read more about azomite and zeolite, check out Ask Ruth from July 2012.



Author: OGS

Organic Growers School is a non-profit organization providing organic education since 1993. Our mission is to inspire, educate, and support people in our region to farm, garden, and live organically.