Fertilizing plants is an interesting topic. We hear a lot of different approaches to feeding your garden. Here's what we know, and it should help you successfully provide what your plants need, so they provide you with ample harvests.


NPK Ratios

When you pick up a bag of plant fertilizer, it has an NPK ratio stamped on its label. NPK means Nitrogen-Phosphate-Potassium, and they appear in a 10-10-10 format. It is always in the Nitrogen, Phosphate, Potassium order, and the numbers correspond to the percentage of N, P, or K in the bag. An NPK label that is 10-10-10 means the bag has 10% Nitrogen, 10% phosphate, and 10% potassium. Those numbers will change. Sometimes they will be 0-12-5 or 24-5-5 or another combination.

Plants go through several growth phases. Their initial sprouting and growing phase requires nitrogen to produce leaves. Potassium helps the plant break down chemicals and produce photosynthesis, and it allows plants to produce healthy roots and stems. Phosphorus helps produce vigorous growth, blossom, and fruit.

It is essential to understand that too much N, P, or K can damage the plant and even kill it.



Compost is one of the most beautiful things you can give plants. It represents the humus layer of the soil, and not only is it full of plant nutrients, but it is also full of life. The microbial life in the ground helps process complex chemicals and break them down into usable formats for plants, especially nitrogen.

Compost and fertilizers help build nutrient-rich soil, which allows most plants to thrive. Some plants prefer poor soil. However, most garden plants prefer soil that is full of nutrients.


When to Fertilize

You fertilize plants at different times of their growth. For example, fertilize before sowing seeds or transplanting seedlings with a balanced fertilizer 10-10-10 or even 5-5-5. Then, switch to a low-nitrogen fertilizer when the plant begins to flower, such as a 5-10-10. The plant will focus on producing blossoms and fruit during fruiting rather than leaves, so it needs less nitrogen.


How to Fertilize

Work the fertilizer into the soil early in the year. If you are using compost, it should be aged. Too much fertilizer will burn plants and potentially kill them. Too little, and they will starve, grow straggly, and produce very little fruit. Top dress means adding fertilizer to the top of the soil and allowing daily watering to transport it to the plant roots. You would top-dress plants during the flowering and fruiting stage or as a booster if the plants were struggling to stay green.

Liquid fertilizers are generally applied once the plant is established. Some can be sprayed onto the plants while others are added to water and applied to the soil. Fish emulsion is an excellent liquid fertilizer.

How you fertilize plants comes down to the plants themselves. Some plants, such as tomatoes, are heavy feeders and need fertilizer; peas and beans will help bind nitrogen in the soil and usually do not need fertilizer.

Let us know if you have questions about fertilizer or fertilizing. We are happy to help.

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