The best Kentucky Bluegrass fertilizer depends on the time of year and application. In early spring, a gentle slow-release fertilizer with phosphorus and high iron content is best for promoting root growth and green color. In late spring and fall, a higher nitrogen fertilizer should be used to promote a thick lawn. Specialized fertilizers are required when overseeding or installing new sod.
- For early spring and late summer, use a slow-release fertilizer with phosphorus and iron.
- In late spring and fall, spread a high-nitrogen fertilizer with potassium to help your lawn grow thick and resist diseases
- If you are seeding Kentucky Bluegrass or laying sod, use a specialized lawn starter fertilizer to help seed and sod develop strong roots.
There is no one perfect fertilizer for Kentucky Bluegrass. At different points of its lifecycle it needs different nutrients. Too much nitrogen in early spring can force blade growth and weaken roots, while a too-gentle fertilizer in early fall won’t give your Bluegrass enough fuel to grow to its full potential.
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5 Best Fertilizers for Kentucky Bluegrass
Kentucky Bluegrass is a unique grass and its fertilizer needs reflect that. It is a fast-growing grass that needs relatively large amounts of fertilizer to thrive. However, it is very easily burned by fertilizer overload, so it’s important to choose the optimal product and apply it at the right time.
- Kentucky Bluegrass requires 4–6 pounds of nitrogen per 1,000 square feet, annually.
- Because it is very prone to fertilizer burn, Kentucky Bluegrass benefits from slow-release, non-burning fertilizers.
- Kentucky Bluegrass spreads to thicken and repair itself via rhizomes (roots), not aboveground runners. This means Bluegrass needs more phosphorus than other grass types, to drive root growth in spring and fall.
To meet the needs of Kentucky Bluegrass throughout the year, and in all stages of growth, we have assembled our top fertilizers. These products will make maintaining a lush Bluegrass lawn easy.
Best Spring Fertilizer for Kentucky Bluegrass
Milorganite is our top pick for a spring Kentucky Bluegrass fertilizer. It’s a great choice because Milorganite contains both nitrogen and phosphorus. Phosphorus drives the root growth Kentucky Bluegrass undergoes in spring. A high-nitrogen fertilizer without phosphorus applied early in spring can force your lawn to grow long blades and neglect its roots.
- Slow-release nitrogen fertilizer that won’t burn your lawn.
- Contains iron to promote rich, green color.
- Delivers phosphorus, which encourages root growth and helps Kentucky Bluegrass spread faster.
- Organic, sustainable fertilizer made from recycled wastewater.
Milorganite is manufactured by kiln-baking the microbes that feed on wastewater. When added to your soil in the right amounts, these microbes release nitrogen to your lawn as needed. This results in a fertilizer that won’t burn your lawn.
Best Fall Fertilizer for Kentucky Bluegrass
Fall is the time to use Scotts Turf Builder. Kentucky Bluegrass experiences its largest growth spurt in fall, as temperatures fall from summer highs. Without adequate nutrients at this time, your Bluegrass will falter and struggle. This high-nitrogen fertilizer from Scotts is perfect for fueling your lawn at this time.
- Contains high levels of nitrogen to support the fall boom in Kentucky Bluegrass growth.
- Includes potassium, which helps Kentucky Bluegrass resist disease and drought.
- When applied in fall, allows Kentucky Bluegrass to store energy for next spring’s green-up.
With cooler fall temperatures reducing the risk of fertilizer burn, it’s time to go all out and provide your Bluegrass with the nitrogen it needs to maintain lush growth. When combined with Milorganite from the spring, your lawn will be ready for the winter ahead.
Best Fertilizer for Kentucky Bluegrass Seed
Scotts Starter Food is our choice for kickstarting the development of your Kentucky Bluegrass seeds. Whether you seed Bluegrass in spring or fall, this is the fertilizer for the job. It blends 24% nitrogen with 25% phosphorus. This simultaneously causes more grass seeds to sprout and helps them form strong roots. This means more seedlings will arrive and survive.
- Nitrogen content encourages sprouting and initial blade growth to jumpstart photosynthesis.
- High phosphorus content prioritizes seed rooting, causing your seedlings to establish themselves and spread fast.
- Can be used when seeding bare patches of soil or spread throughout the yard when overseeding.
Spread Scotts Starter Food at the same time you spread your Kentucky Bluegrass seeds for best results. As you water your seeds to promote germination, you will simultaneously water the Starter Food into the soil, where it can fuel the seedlings’ growth.
Best Fertilizer for Kentucky Bluegrass Sod
If you are installing a new Kentucky Bluegrass lawn from sod or plugs, Pennington UltraGreen Starter Fertilizer is our top choice. This formula contains the essentials for new sod, to encourage quick rooting, fast growth, and green color.
- Contains balanced nitrogen and phosphorus to help take root and grow quickly.
- Includes iron for green color, which can help sod repair from the stress of installation.
- Contains a balance of fast-release and slow-release nitrogen for the initial boost sod needs, as well as continued growth for 8–12 weeks.
With Pennington UltraGreen, your sod lawn will become a seamless, established carpet of Bluegrass turf in just a few weeks. Additionally, the high phosphorus content will help Kentucky Bluegrass plugs spread quickly to fill in your lawn.
- Great starter fertilizer for new seed or sod.
- You can also use Pennington UltraGreen for overseeding or on an existing lawn.
- 5% Iron promotes a deep, thick, lush lawn.
Best Natural Fertilizer for Kentucky Bluegrass
Purely Organic Lawn Food lives up to its name. This plant-derived fertilizer provides the nitrogen and potassium required for established Kentucky Bluegrass lawns. It will provide green color, growth, and help your Bluegrass resist drought and disease. The bonus? It does all this without any chemicals or synthetic fertilizers.
- Is balanced with nitrogen and potassium—perfect for late-spring and fall applications.
- Organic fertilizer that is gentle on your lawn, reducing the risk of fertilizer burn.
An all-natural Kentucky Bluegrass fertilizer schedule can be created by applying Milorganite in early spring and late summer, along with applications of Purely Organic Lawn Food in late spring and fall.
How to Choose the Best Fertilizer for Kentucky Bluegrass
To select the best fertilizer for your Kentucky Bluegrass, use one with nitrogen and phosphorus in early spring. Then, in late spring and fall, apply a high-nitrogen fertilizer. Lawn starter fertilizers are a must for promoting the health of Kentucky Bluegrass seed and sod. Look for products where the phosphorus content is higher than the nitrogen content.
There are many options on the market for Kentucky Bluegrass fertilizer, but the best include a balance of nutrients tailored for this hungry, easily-burned grass. Use slow-release fertilizers in warm weather, and apply natural fertilizers to reduce the risk of fertilizer burn. This will protect your grass and make maintenance a breeze.