A soil test is the only real way you can be sure your lawn is getting the proper nutrients.
Why Test Your Soil
Whether it’s for your lawn, or garden, a soil test will give you valuable information regarding your soils nutrient levels, as well as pH. Without a soil test, there’s no real way to know how healthy your soil is.
What Do Soil Tests Test For?
Different soil tests test for different things. But almost all tests will test for pH. The correct pH is important and plays a big role in the soils ability to absorb nutrients.
Most tests will also test for the 3 main macro nutrients which are nitrogen, phosphorus, and potassium. These 3 nutrients are necessary for healthy lawns, plants, and vegetables.
How to Test Your Soil
When it comes to soil testing do it yourselfers usually do one of 3 options:
- Submit a sample to a local University Extension Program or Garden Center.
- Use an instant test such as (amazon affiliate) Rapitest
- Use a mail in soil testing service such as Yard Mastery
My main issue with getting a soil test at an extension program or local garden center is they can be over complicated. I’ve seen soil tests 10-20 pages long with really confusing explanations. There’s definitely nothing wrong with an in depth analysis but for most do it yourselfers it can be a little overwhelming.
Another option is to use an instant at home test with a product such as (amazon affiliate) Rapitest. It’s great to have the convenience of an instant test, and also this is a very budget friendly option. The main problem with this kind of test is it can be hard to interpret results and overall they are less accurate. With the Rapitest specially I find the potassium results to always be pretty off of lab tested results. Overall, this test is better than nothing and will most likely be good enough to give you a broad idea of your macro nutrient availability.
My favorite test by far is the mail in soil test by Yard Mastery. After ordering they send you a small kit with everything you need including instructions. You simply take a soil sample from your lawn or garden and place it in the liquid they provide you. Then you mail it back to them and the sample gets tested in a lab. The results come back quickly and in a very clear way. It’s not overwhelming and in fact they give you recommendations of fertilizers that will help you get balanced, or remain balanced.
How to Fix PH Balance
Most grass types and plants grow best in a pH of 6-7. If your pH test comes back low (meaning too acidic) then lime your lawn or garden beds to make it more alkaline.
If your soils pH is too high (meaning too alkaline) make it more acidic by adding sulfur or iron sulfate.
How to Read a Soil Test
Take a look at a soil test that I took of my lawn last year using Yard Mastery’s test:
Start With PH
Always start with pH. With out the correct pH your lawn won’t be able to absorb nutrients in the fertilizer. Looking at the test results above I know I could use a Lime Application to increase pH. I went ahead and did this in early spring once the soil thawed.
Look at Macronutrients
Next, focus on the Macronutrients to the left. The first 3 macronutrients are N, P, and K. These are the most important to focus on and those are the 3 main numbers you see on a label of fertilizer (ex. 24-4-8). To learn more about NPK and how to read a fertilizer label check this out: N-P-K
You can see from this test that I’m low in Nitrogen, Phosphorus, and Potassium.
Here’s where things get a little confusing. You would think based off of these results that I should get a fertilizer with a little nitrogen, a lot of phosphorus, and also a lot of potassium and everything should be at optimal levels. But that’s not really how it works.
For the most part your lawn needs, and uses, nitrogen more than the other nutrients. In other words even though the results above show that I’m close to ideal nitrogen levels, I’m going to fertilize with a fertilizer that’s higher in nitrogen than the other nutrients because it’s going to get used up at a faster rate. I do however want to make sure that I’m putting down nitrogen fertilizers that contain P and K in a relatively high proportion.
The best analogy I can use to describe this is the human body. Let’s say all your nutrition comes from drinking one special shake a day (not recommended by the way!). This shake would need to contain mostly water, some proteins, and even some fat. Think of the water in the shake as being the nitrogen in your lawn.
Now if you go to the doctor and he takes a blood test and says your protein and fat levels are low, you need to adjust the shake. He’s still going to recommend the shake is mostly water but he will increase the levels of protein and fat in the shake. Therefor the shake will be richer in protein and fat. That’s pretty much how I want you to picture your lawns health. Nitrogen is the driver, the other nutrients are there for the ride.
Based on the soil test above I’m going use my go to fertilizer Milorganite 6-4-0 for a couple of treatments. I know that this is going to get me a lot of phosphorus which is very much needed. In this case the ratio of nitrogen to phosphorus is 6 to 4. Picture your doctor prescribed shake. That means he’s telling you to have a lot of protein relative to water, almost just as much.
Now I also know that I need potassium in my lawn and the Milorganite doesn’t have any (representing the 0 in the 6-4-0). So after a first application of Milorganite I switched to this product: Lawn Restore 9-0-2. In this case the nitrogen to potassium ratio was 9 to 2. Honestly I would have liked a richer concentration of potassium but this is what I found locally.
For the most part I flipped back and forth between the Milorganite and the Lawn Restore with the exception of applying the Lawn Restore twice in a row (substiuting it for one of the Milorganite applications.) Again, I did this to keep things balanced. I know that the Milorganite is rich in phosphorus and I wanted to play catch up with potassium.
One other thing to consider is I’m being a little general in my claim that your lawn needs nitrogen more than anything else. While this is true for most of the year when your lawn is actively growing and weather conditions are ideal, it’s not true for other times of the year. During times of stress your lawn benefits from backing off on nitrogen and instead going a little heavier on potassium.
Cool season lawns for example take a beating in the middle of the summer. Instead of pushing blade growth with nitrogen and stressing the lawn out more, it’s wiser to feed with higher levels of potassium.
A specialty fertilizer called Stress Blend 7-0-20 heading into summer is a great way to protect your lawn from harsh conditions. This Stress Blend fertilizer can be considered a specialty fertilizer in that it breaks away from our rule that nitrogen is the driver. For warm season lawns, grass is more stressed out when coming out of dormancy in the spring. In this case the Stress Blend is needed more in the spring.
Another specialty fertilizer would be a starter fertilizer. Starter fertilizers are used when growing new seed, laying sod, or doing renovations such as top dressing, and/or core aerating and overseeding. In this case you want a starter fertilizer that contains a high middle number (phosphorus). This helps aid in root development. So you might see a starter fertilizer with numbers that look like this for example: 16-21-2.
What about Micronutrients?
Honestly, don’t go too crazy trying to adjust micronutrient levels if just starting out. The great part about using fertilizers like Milorganite that are mostly organic is they usually have some micronutrients as well. Iron is the most important micronutrient since this will help you get that dark green color. Yard Mastery has a great line of fertilizers that also contain micronutrients so I highly recommend you check them out here: Yard Mastery Fertilizers
Lastly, just remember, the soil test is there to point you in the right direction. You shouldn’t try to solve all of your nutrient problems with one fertilizer application. Think of the soil test as a nutritional plan for your lawn. And don’t get too in your head and start over analyzing. At the end of the day you have to put down products that you can get in your area, or at least get delivered to you. There is always a plan you can come up with using just the products at your local hardware store or big box store if needed.
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