Our backyard is an absolute mud pit. We had a company place topsoil on it last year, but it was not great soil. There was tons of trash and glass that we are STILL picking out. We really should have gotten a refund and had them redo the whole thing. Anyway, last fall we overseeded with Fescue grass. Everything seemed to be going well, many of the seeds sprouted and were growing well for a couple of months. Unfortunately, almost all of this grass died and now our backyward looks like someone just spread out mud, stomped all around, and left grass remants.
So, now I am researching the best way to fix our backyard. Some good news – we did a great job regrowing the front yard after having that torn up. When our sewer line needed to be replaced the whole yard was torn up and we needed to regrow the lawn. I think the key thing that helped here was that a large portion of the yard was already tilled up. We hoed weeds to remove the rest and used an electric tiller to aerate and till the soil. We then overseeded with Fescue seed and a couple weeks later, voila! Grass! And this grass grew for a couple of months. The weather was on our side since the summer was warm, not hot, and had plenty of rain. Our front yard looks great, so I know we can grow grass…just need to refocus on the backyard.
The first step is to test the soil. Now, you can send soil off to the county to be officially tested, but it’s a lot simpler and easier to just do it yourself. It’s super easy to find a good soil kit online (hello Amazon!). The one I ordered is a Luster Leaf rapitest Soil Test Kit that got pretty good reviews on Amazon. This kit tests pH, nitrogen, phosphorus, and potassium levels. Being the plant scientist that I am, I wanted to go over why these different nutrients are so important for the health of a lawn. The ideal pH range is between 6.0 and 6.5 in order for the lawn to get the most of the nutrients available. When the pH is acidic, lime can be added to neutralize the pH. If it is too basic, sulfur can be added. The kit makes it super easy to figure test the soil. For the pH test, I had to add a little bit of soil (dug about 6-8 inch below the surface) and add water according to the directions. You then add the appropriate colored pill that contains the pH ingredient, shake and allow to settle. You then read the results by aiming the container at light. Ideally, this would be sunlight. Our pH is around 6.5, maybe 7.0 so our lawn is OK in the pH department.
The next three nutrients, nitrogen, phosphorus, and potassium were measured by a similar process. The main difference here was that the soil needed to settle for about 24 hr before being added to the plastic containers. The correct colored powder was added, mixed well with the soil, and then allowed to settle and react for 15 min. I then checked the coloring with the various levels of nutrients.
Nitrogen is required for foliage growth, plant growth, and color. Nitrogen-rich mulch can be added to help retain moisture as well as regulating temperature. The addition of mulch can also help prevent weeds from growing. Lawns require fertilizer with higher amounts of nitrogen than any other nutrient. After checking the nitrogen levels in our soil, the nitrogen level is deficient or depleted. This may be one explanation as to why there is has been low to no growth of the grass.
Phosphorus is needed for stem and root growth. In fact, P helps stimulate early root growth as well as promoting rigorous growth and stem strength. The P in our soil is between deficient and adequate, so not much will need to be added. There is quite the controversy with having P in fertilizer. When nutrients from fertilizer are not absorbed before a rainfall, excess nutrients are in the run-off. Phosphorous has been linked to promoting algal blooms, which can lead to oxygen deficiency and fish kills. There are tons of studies on this, and I learned a lot about it during my environmental issues class during my Ph.D. Suffice to say, this is why phosphorous has been banned from laundry detergents and there is a correlation between P and eventual fish kills.
Potassium (K) is considered a macronutrient and helps with internal processes of things like photosynthesis and respiration. K also helps to strengthen cell walls, which helps the grass blades with withstanding environmental stressors. This nutrient can also be added using fertilizer. Another way to add K, is to leave grass clippings on the lawn which allows reabsorption of K into the roots. The K in the soil is also between deficient and adequate.
To redo the back yard, we need to remove all of the previous weeds and grass. A weed killer containing glyphosphate will kill every living plant in the ground. It is also a good idea to let the ground sit for about a week before seeding. This allows us to remove any weeds that may pop up between addition of the herbicide and seeding. The yard will then need to be tilled and aerated. It is also recommended that you wait an additional week or two to remove any dormant weeds that may pop up.
Next, fertilizer and/or lime (if needed) should be added. Choosing the appropriate fertilizer is key to a healthy lawn. Bags of fertlizer have three numbers on them with the first representing N, the second for P, and the last number for K. These numbers are percentages of the total in the bag. A new lawn needs more P to promote root growth. Once established, you can use a fertilizer with higher amounts of N.
Seed can now be laid down! For our area, tall Fescue is recommended. This is what we planted in the front yard and it grew well. We don’t get as much sun in the backyard, but we should be able to get enough oblique sun throughout the day to promote growth. Once the seed is laid down, it is also a good idea to put down peat moss or manure which will act as both a protective layer and mulch. Having mulch will reduce how much the lawn needs to be watered. The seeded lawn will now need to be watered consistently. If all goes well, we will have a new lawn!