Fertilizers provide essential nutrients to plants at every stage of growth. Established and newly emerging seedlings have different nutritional needs. This is why we have starter fertilizers and regular fertilizers. So, can you use starter fertilizer on an established lawn?
No, you shouldn’t use starter fertilizer on established lawns. It doesn’t provide the right nutrients to maintain mature grass. Use a well-balanced, regular fertilizer instead to support established lawns year-round.
Starter Fertilizer on Established Lawn – Reasons Not to Use
Lawn starter fertilizer is basically formulated for new grass seed or sod. These broad-range fertilizers are best applied at the seeding or sod-laying stage. When applied, starter fertilizer helps grass seedlings or sod establish more quickly into a thick, healthy lawn.
Starter fertilizers for lawns come in different NPK ratios. Still, they usually have balanced amounts of nitrogen, phosphorus, and potassium, or two parts nitrogen and one part each of phosphorus and potassium. Common lawn starter fertilizers include 10-10-10, 20-10-10, and 16-8-8.
Plants usually need nitrogen for enhanced growth and green pigmentation, while phosphorus supports the growth of various plant tissues, including roots. Potassium promotes hardiness and resistance to disease, drought, and harsh winter conditions.
Early-stage grass seedlings have higher energy and nutrient needs and thus require large amounts of nitrogen and phosphorus, which starter fertilizers provide.
Using starter fertilizer on established lawns is strongly not recommended. This type of lawn fertilizer will not provide the optimum, well-balanced nutrition mature grass needs. The higher phosphorus levels in the fertilizer are also unhealthy for established turf.
Excess phosphorus in the soil interferes with the absorption of nitrogen and other micronutrients such as zinc, iron, cobalt, and calcium. This can lead to stunted grass growth, weed growth, and eventually grass death.
Lawn Starter Fertilizer vs Regular Fertilizers
Regular lawn fertilizers are designed to maintain mature lawn grasses. They are usually applied throughout the year to meet the grasses’ nutritional needs. They contain nitrogen, phosphorus, and potassium in balanced levels that benefit mature turf.
According to David M. Kopec, a turf specialist at the University of Arizona Extension, the main difference between a lawn starter fertilizer and regular fertilizer is the phosphorus content. Starter fertilizers usually contain more phosphorus than regular fertilizers (20% or more).
Kopec further states that starter fertilizers need quick-release nitrogen. This makes it easier for young, tender roots to access nutrients. Regular fertilizer is a slow-release formula that benefits mature or established lawn grasses over many months.
Apply starter fertilizer before seeding. Applying starter fertilizer directly can burn new grass seedlings or sod. Regular fertilizer, on the other hand, is usually applied four to eight weeks after the first application of starter fertilizer. By then, the grass is stronger and can absorb nutrients from the fertilizer without problems.
How do you Apply Starter fertilizer?
Before you start a new lawn or repair those bare spots, it might be important to get your soil tested. Take a soil sample to a nearby garden center or cooperative extension to determine the available nitrogen, phosphorus, and potassium. This will help you choose a better starter fertilizer when you seed or lay sod.
If you are seeding, a starter fertilizer with equal or higher levels of nitrogen and phosphorus will be helpful. If you are laying sod, you will need more phosphorus to help the cut roots establish faster. Once you have made your decision, you can now apply the fertilizer as follows:
- Carefully read and follow the application instructions on the fertilizer packaging. Ideally, apply around 0.5 to 1 pound of nitrogen per 1000 square feet. Applying more than this can burn your grass or run off into stormwater drains.
- Apply your starter fertilizer before you lay the sod. For seeding, you can apply it before or after planting. If you apply fertilizer to newly laid sod, it can easily burn the grass, especially if it isn’t watered enough.
- Work the fertilizer and any other recommended amendments 4 to 6 inches into the soil using a rake.
- Finally, water the planted area and cover it with a thin layer of straw or mulch to retain moisture, protect the seed from animals, and speed germination. Note that consistent watering is required for effective seed germination or establishment of the installed sod.
Once the grass is starting to grow, you can apply a regular fertilizer after 4 to 8 weeks, preferably when the grass is 1 to 1 ½ inches tall. Once your lawn is fully established, you can follow the recommended yearly lawn fertilizing schedule.
Final Thought
You need to use a starter fertilizer when starting a new lawn or fixing bare spots through seeding or laying sod. Starter fertilizer isn’t beneficial for established lawns. Start using regular fertilizer 4 to 8 weeks after using starter fertilizer to maintain your lawn’s health. Pair this with other lawn care practices, including watering, mowing, and aerating.
Frequently Asked Questions
What is starter fertilizer used for?
Starter fertilizer helps new grass seed or sod establish strong roots and healthy growth during the early stages of development.
Can you use starter fertilizer on an established lawn?
No, starter fertilizer is not recommended for established lawns. It’s designed for new grass seed or newly laid sod and doesn’t provide the balanced nutrients mature grass needs.
What is the difference between starter fertilizer and regular fertilizer?
Starter fertilizer contains higher phosphorus levels to support root development in new grass, while regular fertilizer is formulated to maintain healthy, mature lawns with balanced nutrients over time.
When should starter fertilizer be applied?
Apply starter fertilizer before or during seeding, or before laying sod.
How long after using starter fertilizer can I apply regular fertilizer?
Apply regular fertilizer about 4 to 8 weeks after starter fertilizer, once the grass is stronger and more established.
Can too much starter fertilizer damage grass?
Yes, applying too much starter fertilizer can burn grass seedlings or sod and may also cause nutrient runoff into nearby water systems.
Is regular fertilizer suitable for newly seeded lawns?
Regular fertilizer is generally not ideal for newly seeded lawns because it may not provide enough phosphorus for early root growth. Starter fertilizer is the better choice for newly seeded lawns.
