A Guide to Fertilizing An Organic Garden To Maximize Growth

If you want happy, healthy plants, fertilizing is vital. That’s probably why some of the most common gardening questions have to do with fertilizing.

Too much fertilizer can actually harm plants, and waste money and time. Not enough fertilizer or fertilizer applied at the wrong time can mean stressed plants and decreased yields. Just like Goldilocks, the goal is to get it “just right”.

I’ve already written about how to add nitrogen to soil, the advantages of Trifecta+ fertilizer, the fertilization of fruit trees and perennials, and the best fertilizer for vegetable gardens. Plus, I’ve shared tutorials on making homemade fertilizers, like how to make bone meal fertilizer, seaweed fertilizer, compost tea, vermicompost, and weed tea.

If you are still wondering when to fertilize, when not to fertilize, how much fertilizer to use, and the other do’s and don’ts of fertilizing an organic garden, you’re in the right place! I want to answer those questions here so you can fertilize with confidence.

Types of Fertilizer

If your goal is to grow an organic garden, it is important to first understand the three different types of fertilizers and their ingredients. They are:

• Organic Fertilizer - Made from naturally occurring ingredients, like blood meal, rock phosphate, or worm castings, for example. This is the type of fertilizer that I feel most comfortable with. 

• Synthetic Fertilizer - These are made in a lab and not found in nature. This includes chemical compounds like ammonium nitrate, ammonium phosphate, and super phosphate. While they may be very effective at getting the job done, some of these man-made compounds can create heavy salts in the soil because they don’t break down like naturally occurring chemicals do.

• Organically Synthetic Fertilizer - This category can be confusing because these fertilizers contain chemical compounds that can be found in nature, but are made in a lab. This often includes things that are too rare or too expensive to source from nature, like magnesium sulfate (epsom salt) and uria.

Fertilizing An Organic Garden

To grow an “organic” garden, all fertilizers, soil amendments, pesticides, and fungicides used on the crops must contain only naturally occurring ingredients. (Here is more information on organic pesticides and organic fungicides.) Organic gardening has grown in popularity as more and more people are trying to reduce potential health risks by limiting exposure to toxic and unnatural synthetic chemicals, especially in the food they consume.

But there are more reasons to love organic gardening! It often goes hand in hand with prioritizing soil health, preserving heirloom heritage plants and biodiversity, and sustainable growing practices. 

If you are looking for an organic fertilizer to ensure your peace of mind, check out VegaGrow! This vegan friendly fertilizer is all-natural, all-purpose, and all its components are certified organic and GMO-free! VegaGrow has the essential macronutrients plus 65 micronutrients, beneficial bacteria, and beneficial fungi your plants need.

Best Time to Fertilize

I make it a practice to apply fertilizer in the planting hole whenever I plant something in the garden. It's far better to put the fertilizer in the planting hole where the roots will come in contact with it so the plant can start uptaking nutrients right away. The faster a plant starts uptaking nutrients, the faster it can grow, become established, and start producing food or flowers.

To fertilize at the time of planting, dig the hole where you will be planting, sprinkle the recommended amount of fertilizer into the hole, and mix the fertilizer into loose soil. Plant as usual and water thoroughly. 

How to Apply Fertilizer Using the Top Dressing Method

I like to use this method when fertilizing established plants and to delay fertilizing when direct sowing seeds, like beans, carrots, beets, or lettuce. For these seeds, I rely on soil fertility to get them started. This gives the young, tender seedlings time to get growing before fertilizing so that the likelihood of them getting burned is a lot less.

To top dress with fertilizer, sprinkle the recommended amount of fertilizer onto the soil surface around the plant. Sprinkle fertilizer close to the base for small young plants and over an increasingly larger area according to the size of the plant. 

Then, gently rake it into the soil. Avoid vigorous raking to prevent damaging roots. Water generously after working fertilizer into the soil to allow nutrients to travel down. 

When Not To Fertilize

You do not need to fertilize if your plants are nice and green, if they are producing plenty of food, and if they are not looking stressed in any way. Those are indicators that they plant is growing just fine and has what it needs.

The criteria I look for to know when a plant needs more fertilizer is the color of the leaves. Look at the leaves halfway up the plant. If you see signs of yellowing, stunted growth, or the undersides of the leaves are looking slightly purple or red halfway up the plant, that is an indication that you need to fertilize. 

Pro-Tip: Don’t make the mistake of judging by the lower leaves of the plant! Older, more mature leaves may slowly be dying as the plant grows and that is not an indicator of needing fertilization.

How Much Fertilizer to Use

Photo courtesy of https://extension.umd.edu/resource/garden-fertilizer-basics/

In the blog post on Trifecta+ fertilizer, there is a chart that tells you exactly how much Trifecta fertilizer each type of garden plant needs and how many feedings a year it needs. But fertilizers are not all the same, so follow the application instructions on whichever type of fertilizer you decide to use.

Beyond that, use observation to tell if your plants need additional fertilizer. I would rather have the plant tell me it’s not fine than for me to overfertilize. Overfertilizing not only wastes time, but also money and can potentially stifle development, dramatically reduce fruit development, or even kill the plant.

How do you know if you have overfertilized? If you overfertilize root crops like carrots or radishes, you will have beautiful tops but very small roots. If you overfertilize fruiting plants like tomatoes or beans, you will have beautiful green, plants but very few fruits. 

And in more extreme cases, your plants will show signs of fertilizer burn. Fertilizer burn causes discolored brown or yellow leaves that may have crunchy edges. 

Do’s And Don’ts of Fertilizing an Organic Garden

These mistakes and misconceptions are very common. I see them happen all the time, not only with beginning gardeners but even with more advanced gardeners. I hope to save you from these fertilizing blunders: