When overseeding a lawn, it’s tempting to use a lot of grass seed in hopes of getting thicker, greener grass as quickly as possible. But is there such a thing as using too much seed when overseeding? The short answer is yes.
How Much Seed is Recommended for Overseeding?
Most experts recommend using between 5-10 pounds of grass seed per 1000 square feet when overseeding. This amount provides adequate coverage without wasting excess seed or creating problems like overcrowding.
Here are some general seeding rate guidelines for overseeding:
| Lawn Type | Seeding Rate |
|---|---|
| Cool season grasses like fescue and bluegrass | 5-8 lbs per 1000 sq ft |
| Warm season grasses like bermuda and zoysia | 8-10 lbs per 1000 sq ft |
These rates allow for good turf coverage without going overboard. The actual amount needed depends on the grass type, lawn thickness, and extent of bare spots or thinning.
What Happens if You Use Too Much Seed?
Using excessive amounts of grass seed can create the following problems:
- Waste of seed – More seed won’t necessarily produce thicker turf, so you’ll be wasting money on extra seed.
- Overcrowding – Too many seeds germinating in the same area causes competition for resources, resulting in stunted growth.
- Disease – Overcrowded, stressed grass is more prone to fungal diseases.
- Thin turf – When plants compete for resources, they often grow upright and produce less blades, resulting in thinner looking grass.
- Extra mowing – Lush overgrowth from overseeding requires more frequent mowing to keep it maintained.
Waste of Seed
Applying seed at double or triple the recommended rates in hopes of getting thicker turf simply doesn’t work. Sure, more seeds will germinate, but they’ll be crowded and competing for resources. The end result will be patches of stunted, stressed grass.
Studies have shown that once the proper amount of seed is used for good coverage, adding more won’t increase turf density. The excess is just wasted.
Overcrowding
When lots of seeds germinate in a small area, the emerging grass plants have to compete for water, nutrients, and light. This leads to stressed, thin turf.
Overcrowded grass also tends to grow more upright as plants stretch to reach sunlight. This causes them to produce fewer blades, reducing density.
Disease Problems
The stress of overcrowding leaves grass more vulnerable to diseases like brown patch, dollar spot, and pythium blight. Fungal pathogens take advantage of thin, crowded, weakened turf.
Good cultural practices like proper seeding rates, mowing, and fertilization produce healthy, vigorous grass that’s more disease resistant.
Thinner Turf
Although it seems counterintuitive, using too high a seeding rate can actually lead to thinner, wispier grass rather than a thicker lawn. This goes back to the effects of overcrowding.
When grass plants compete for resources, they put energy into growing upright rather than producing more blades. This results in sparse, thin looking turf.
Extra Mowing
Overseeding with too much seed produces rapid, lush growth as the seeds germinate. But this requires frequent mowing to keep the grass at its proper height. Otherwise, it gets too long and floppy.
Proper seeding rates lead to a more moderate rate of growth that doesn’t need mowing more than once a week in peak growth periods.
Signs You Used Too Much Seed
Here are some visible signs that indicate you may have used excessive seed when overseeding:
- Dense clumps of new grass – New seeds should germinate evenly, not in thick bunches.
- Stunted, yellowing grass – Overcrowded, stressed grass often lacks vigor.
- Increased disease problems – Fungal diseases may appear if grass is weak and thin.
- Rapid, excessive growth – Lush, excessive growth from overseeding requires frequent mowing.
- Thin, upright growth habit – Overcrowded grass often grows upright with fewer blades.
If your overseeding results in any of these issues, you likely used more seed than necessary. Stick to the recommended rates next time.
Correcting Problems from Using Too Much Seed
Here are some tips for getting your lawn back on track if you’ve used excessive seed when overseeding:
Raise Mowing Height
Letting the grass grow a little taller reduces competition between plants by allowing more light penetration. Gradually raise cutting height over a period of weeks.
Aerate the Lawn
Aeration punches holes in the soil, allowing better air and water movement. This helps relieve compaction and improves conditions for crowded grass.
Apply Fungicide
If fungal diseases are present, apply appropriate fungicide products to protect grass. Improve airflow and sunlight penetration to affected areas.
Overseed Again
Overseed again at the proper rate if the lawn is still thin or has bare patches after addressing compaction, disease, and mowing height. This fills in weak spots.
Fertilize Lightly
Applying extra nitrogen too soon can cause more excessive growth. But light fertilization provides nutrients without pushing rapid growth. Use a balanced fertilizer at half the normal rate.
Reseed Bare Areas
Completely remove grass in remaining bare spots, prepare the soil, and plant new seed. Water gently to establish the seedlings without washing them away.
How to Determine the Right Seeding Rate
Figuring out the right amount of seed for overseeding involves assessing the lawn and making some calculations. Follow these steps:
- Measure your total lawn size in square feet using length x width. Don’t subtract non-lawn areas.
- Determine the seeding rate based on grass type from the chart above.
- Multiply lawn size x seeding rate to get total seed needed.
- Add 10-20% extra for overlaps and irregular areas.
- Divide by seed bag size to determine number of bags to buy.
You may need to adjust based on lawn thickness, slope, shade, soil type, and extent of bare spots. But these steps provide an initial starting point to find the right amount of seed.
Example Calculation
For example, an 8,000 sq ft fescue lawn overseeding at 6 lbs per 1000 sq ft would need:
- Lawn size: 8,000 sq ft
- Seeding rate: 6 lbs/1000 sq ft
- 8,000 x 0.006 = 48 lbs of seed needed
- Add 10% extra = 53 lbs total seed
- For 50 lb bags, buy two bags
Best Practices for Overseeding
In addition to proper seeding rates, here are some other tips for overseeding success:
- Mow, dethatch, and aerate before seeding to prep soil.
- Choose quality grass seed suited for your lawn and climate.
- Use proper spreader settings for accurate coverage.
- Seed early fall for cool season grass or early summer for warm season.
- Water lightly and frequently to keep new seeds moist.
- Apply starter fertilizer when seeding to support growth.
- Wait 2-3 weeks after seeding for first mowing.
Conclusion
Using too much grass seed when overseeding won’t generate thicker, healthier grass. It’s just a waste of seed that can create problems. For the best results, determine the right amount of seed based on lawn specifics and expert guidelines. Stick to recommended seeding rates, and supplement with good cultural practices.
With patience and proper seeding techniques, overseeding can thicken up thinning grass and fill in bare spots. But too much of a good thing causes more harm than good when it comes to grass seed. Use moderation, apply what’s needed, and avoid going overboard.