How to Fertilize Soil Effectively [2020 update]

How to Fertilize Soil Effectively – gardens and grass [2020]

Fertilizing soil can be complicated. You have to figure out what fertilizer you need among the hundreds of types available. [5-10-10, 20-10-10, compost, steer manure, ammonium sulfate???]  It’s going to depend on the plants you are growing and the soil type/condition. I’ll help you make some of those decisions.

Fertilizers can turn your garden into a cornucopia of fruits and vegetables or your yard into a golf course putting green. Here’s how and what to use for fertilizer.

Soil Conditions

Plants generally prefer moist, soft soils with lots of organic material mixed in a well draining substrate. So, to simplify this, sand with 8-12″ of organic compost on top in theory is ideal. sandy soil and gravel are excellent for draining. If a soil does not drain well, plant roots can rot from too much water retention.

So, dig up some of your soil and see what it looks like. Is it dry and hard or moist, dark and soft? Or in between?

Generally speaking, it’s always a good idea to add an organic compost to the soil around plants and grass. It will revitalize the soil, add nutrients, modify the texture and increase water retention. Mixing compost with soil also increases aeration. All of these are great for plant life.

Compost does many great things to soil. However it is a slow fertilizer and works over the long haul. It doesn’t change plant growth or health overnight. For rapid fertilization, you may need a non-organic fertilizer like 5-10-10.

Some plants like strawberries prefer acidic soils. If your strawberry garden does not have acidic soil then you might have to add some Ammonium Phosphate 16-20-0 and a soil sulfur. The ideal pH is around 6.0 – 6.1.

A general all-purpose fertilizer would be something like 5-5-5. It’s a well balanced fertilizer. It comes in organic and non-organic flavors. It’s always best to select Organic.

Organic Fertilizers


Compost is the most popular organic fertilizer and is always a safe bet when in doubt what to use. It’s available at any nursery or home improvement store like Lowes and Home Depot.

Compost is decomposed plant material like leaves, grass, wood chips, pine needles and shrub clippings. It’s very easy to apply. Just mix it with the soil around your plants and then add a 2-3″ layer on top of the soil. You’re done for 6 months. It does not matter how much you use. You can never use too much and harm plants. Compost is ideal for vegetable gardens, trees, shrubs and flowers.

For grass, I recommend Composted Steer Manure. It’s finer and works better on a grass yard. Make sure you buy composted steer or composted cow manure. You don’t want raw manure.

Oak Tree + Composted Steer Manure

I have a small Oak tree in my front yard. For years it always had sparse foliage. It was never full of leaves. It kind of looked like the Charley Brown Christmas tree. I watered it regularly buy no change. One year I applied some steer manure compost to the root line. After about 6 months it took on a new life. It grew about 1 foot and is full of bright green leaves. It never looked better.

What a difference!

Spot Composting

Another method of fertilizing a garden or any area is to bury plant material in the soil. It’s better known as Spot Composting. I gather kitchen produce like cucumber ends, carrot peelings, old lettuce, tomatoes, etc and bury it in my backyard or in the garden. It will decompose slowly and condition the soil. It will also attract beneficial microbes, insects and worms. Just dig a hole and throw some veggies in it and cover it up. Done.

Mulch as a Compost

You can buy compost or you can make it yourself like I do. The simplest compost to make is grass clippings from your lawn. I layer the grass clippings 1 inch thick over my garden bed. It will decompose slowly, turn into compost and feed my vegetable plants. Grass mulch helps the soil retain moisture which will prevent the soil from getting dry and rock hard. You’ll use less water in your garden too. Mulch will help prevent weeds from growing in your yard without using herbicides.

Worm Castings

Another all purpose and completely safe organic fertilizer is Worm Castings or worm poop. Plants do extremely well with very little amounts of worm castings. Worm castings provide more nutrients than any compost or fertilizer like say…10-10-5 fertilizer.

Worm castings provide thoroughly broken down nutrients, beneficial bacteria, microbes and enzymes not found in any other fertilizer. It is the Perfect diet for all plants. Think of it as Baby Food for infants…easily digestible with a perfect balance of nutrients.

If you use worm castings, you can spread it around your plants in any amount you like. It will never harm your plants no matter how much you apply. You can use it on top of the soil or mix it in with the soil. Usually you can apply about a tablespoon of worm castings around in each plant in a vegetable garden or several tablespoons around trees and shrubs. A little goes a long way.

You can buy worm castings at some nurseries and home improvement stores or online. It’s usually $20 for a small 2 lb bag.

When to use a compost and when to use a non-organic fertilizer

Compost should be used every 6 months to a year as maintenance. It will continue to fertilize for many months after applying. Once you have healthy plants or grass, this is all you need to do.

If your garden or grass need attention quickly to prevent dying then you might need to use a non-organic fertilizer. Non-organic fertilizers are anything that is produced in a chemical factory like ammonium nitrate or urea or ammonium phosphate. Usually non-organic fertilizers only contain 3 elements,  NPK or Nitrogen, Phosphorus and Potassium and are designated by three numbers aka 5-10-10. This is 5% Nitrogen, 10% Phosphorus and 10% Potassium.

A non-organic fertilizer will release its nutrients quickly, like in hours to a few days. Changes can occur very fast but you need to be careful how much you apply. Too much non-organic fertilizer can burn or kill plants because it “dumps” the nutrients all at once. There is no “time release” to it. Always follow the directions on the fertilizer bag.

How to Apply Fertilizer

You can apply fertilizer to the top of the soil or mix it in the soil. Either way will work since water will pull the fertilizer down through the soil. If using compost, it is beneficial to mix it with the soil. It will help aerate and increase water retention of the soil.

Granular fertilizers, compost and worm castings are easy to spread by hand while liquid fertilizers need to be mixed with water and then sprayed on the soil.

When using any non-organic fertilizers, always follow the directions on the product bag. Too much can be harmful. I recommend using gloves when applying non-organic fertilizers.