Under Sod 4-2-5 is blended into the top 4 to 6 inches of soil before the sod goes down. The label method is incorporation. If you cannot mix it in, use the quarter-rate topical application.
The rate is one 25-pound bag per pallet of sod (500 square feet), which is 50 pounds per 1,000 square feet, blended into the top 4 to 6 inches of soil.
Quick answer
The best sod fertilizer in Connecticut is really two products, in order: an iron-free, low-phosphorus biological pre-plant fertilizer — Under Sod 4-2-5 — worked into the rooting zone on install day, then a no-phosphorus, nitrogen-led maintenance fertilizer once the lawn has knitted down. Connecticut's fertilizer law (C.G.S. § 22-111yy) allows phosphorus when you are establishing new grass with seed or sod, but once the lawn is established the restriction applies — so make the phosphorus decision at install, and go phosphorus-free after unless a soil test shows a need.
Sod fertilizer in Connecticut is two decisions, not one
Most "best sod fertilizer" lists treat a sodded lawn as one feeding problem. In Connecticut it is two, separated by law as much as by biology. On install day, the state's phosphorus law explicitly allows fertilizer used to establish new grass with seed or sod. Once the lawn is established, that exemption no longer applies: phosphorus lawn fertilizer is generally prohibited on an established Connecticut lawn unless a soil test within the previous two years shows a need. The right product for each moment is different — and picking one product for both moments gets at least one of them wrong.
Decision 1 — install day: what goes under the sod
This is the feeding that matters most, because freshly harvested sod arrives nearly rootless and has days to push new roots into the soil beneath it. Under Sod 4-2-5 is built for exactly that zone: an iron-free 4-2-5 biological pre-plant fertilizer with named endomycorrhizae, a *Bacillus* + *Trichoderma* biology package, seaweed extract, and humic and fulvic acid, in a fine SGN 90 granule. Use one 25-pound bag per pallet of sod (500 square feet), which is 50 pounds per 1,000 square feet, blended into the top 4 to 6 inches of soil, then final grade, roll, lay the sod, and water in. Its moderate 2% phosphorus supports root initiation without the spike Connecticut's rules are written to discourage.
The rate is one 25-pound bag per pallet of sod (500 square feet), which is 50 pounds per 1,000 square feet, blended into the top 4 to 6 inches of soil. At that rate it delivers 1 pound of phosphate, 2 pounds of nitrogen and 2.5 pounds of potash per 1,000 square feet, in line with the preplant rates Michigan State publishes, at the 4-inch-plus depth Rutgers and Michigan State publish, for establishing a new lawn when a soil test calls for it. It is spread through roughly 17 tons of soil at a 5-inch midpoint (about 14 tons at 4 inches, 21 at 6) where new roots grow. Incorporation reduces surface exposure; it does not eliminate runoff risk.
How Under Sod is applied
- Spread one 25-pound bag per pallet of sod, 500 square feet (50 pounds per 1,000 square feet), evenly on the prepared, graded soil for blending into the top 4 to 6 inches in the next step.
- Rototill or Harley-rake it into the top 4 to 6 inches.
- Final grade and roll.
- Lay the sod and water in.
What actually goes down per 1,000 square feet
Percentage on the bag is not the same as dose on the lawn. These are the nutrient doses and placements at the rates shown below. Competitor rows are comparison examples, not verified current label rates.
| Product | Comparison rate per 1,000 sq ft | Nitrogen (lb) | Phosphate P2O5 (lb) | Potash K2O (lb) | Placement |
|---|---|---|---|---|---|
| Under Sod 4-2-5 | 50 lb (one bag per pallet) | 2.0 | 1.0 | 2.5 | Blended 4 to 6 inches deep |
| Over Sod 8-0-6 | 12.5 lb (one bag per four pallets) | 1.0 | 0 | 0.75 | Surface, at day 30 |
| Scotts Turf Builder Starter 24-25-4comparison example | 3 lb | 0.72 | 0.75 | 0.12 | Surface |
| Jonathan Green Veri-Green Starter 12-18-8comparison example | 3 lb | 0.36 | 0.54 | 0.24 | Surface |
Under Sod 4-2-5 and Over Sod 8-0-6 rows use this site's own rates. Rows marked "comparison example" use example rates supplied for this comparison; they have not been verified against each manufacturer's current label, which can differ by product version and use. Check the bag in hand. Nutrient pounds are rate times analysis.
Where it ends up in the soil
Soil test first. When not to use Under Sod covers low-phosphorus test results, high-phosphorus results, and local rules.
For the full Connecticut deep dive — Valley sand versus upland till, the UConn soil-test bands, and the law's details — see best fertilizer under sod in Connecticut.
Decision 2 — after it roots: the first-season feeding plan
For the first weeks after install, the job is water, not more fertilizer — the starter is already in the rooting zone. Once the sod has knitted down (gently tug a corner; when it resists, roots have taken), it is an established lawn in the eyes of Connecticut's fertilizer law. From that point, choose a no-phosphorus, nitrogen-led maintenance fertilizer (a zero middle number) unless a recent soil test shows a phosphorus need. For the cool-season grasses laid across Connecticut, the most important maintenance feeding of the year is early fall, which builds density and root reserves before winter.
| Moment | What to use | Why |
|---|---|---|
| Install day | Under Sod 4-2-5 biological pre-plant fertilizer beneath the sod | Establishing with seed or sod is an allowed use under C.G.S. § 22-111yy, and the feed sits in the rooting zone |
| First weeks | Water only | Roots are knitting; the starter is already in place |
| Once established | No-phosphorus, nitrogen-led maintenance fertilizer | Established-lawn phosphorus limits now apply unless a soil test shows a need |
| Early fall | The season's key feeding for cool-season turf | Builds density and root reserves before a New England winter |
Moment
Install day
What to use
Under Sod 4-2-5 biological pre-plant fertilizer beneath the sod
Why
Establishing with seed or sod is an allowed use under C.G.S. § 22-111yy, and the feed sits in the rooting zone
Moment
First weeks
What to use
Water only
Why
Roots are knitting; the starter is already in place
Moment
Once established
What to use
No-phosphorus, nitrogen-led maintenance fertilizer
Why
Established-lawn phosphorus limits now apply unless a soil test shows a need
Moment
Early fall
What to use
The season's key feeding for cool-season turf
Why
Builds density and root reserves before a New England winter
Where Under Sod 4-2-5 fits
Under Sod 4-2-5 handles the install-day half of this plan — the half you cannot redo later. See the full specs or join the notification list for product updates.
Always pair fertilizer choices with a soil test. Connecticut restricts phosphorus lawn fertilizer under C.G.S. § 22-111yy, enacted by Public Act 12-155 and effective January 1, 2013, administered by the Department of Agriculture. Phosphorus fertilizer is generally prohibited on an established lawn unless a soil test (by an approved method, within the previous two years) shows a need, or it is used to establish new grass or repair a lawn with seed or sod — which is the sod-installation case. The rules also limit application on impervious surfaces and call for care near water, and individual towns may add stricter local rules. Under Sod's moderate 2% phosphorus and iron-free formula are the relevant angle in these water-sensitive areas, but always confirm current state and municipal requirements before applying.
Frequently Asked Questions
What is the best sod fertilizer in Connecticut?+
Two products, in order: an iron-free, low-phosphorus biological pre-plant fertilizer — Under Sod 4-2-5 — in the rooting zone on install day, then a no-phosphorus, nitrogen-led maintenance fertilizer once the lawn is established, unless a soil test shows a phosphorus need.
Can I use phosphorus fertilizer on new sod in Connecticut?+
Yes. Under C.G.S. § 22-111yy (Public Act 12-155, effective January 1, 2013), phosphorus fertilizer is generally prohibited on an established lawn unless a recent soil test shows a need or you are establishing new grass or repairing a lawn with seed or sod — which covers a sod install. Applications near water and on impervious surfaces are also limited, and towns may add stricter rules.
What should I feed sod after it is established in Connecticut?+
A no-phosphorus, nitrogen-led maintenance fertilizer, unless a soil test within the previous two years shows a phosphorus need. For Connecticut's cool-season lawns, early fall is the most important feeding of the year.
How much starter fertilizer goes under the sod?+
Under Sod 4-2-5 goes down at one 25-pound bag per pallet of sod (500 square feet), which is 50 pounds per 1,000 square feet, blended into the top 4 to 6 inches of soil. Count your pallets to count your bags.
Keep reading
Step two
Day 30: OVER SOD™ 8-0-6 is step two, a phosphorus-free surface feed with mostly slow-release nitrogen, at one 25-pound bag per four pallets of sod (2,000 square feet), which is 12.5 pounds per 1,000 square feet: about 1 pound of nitrogen, 0.75 pound of potash, and no phosphate. Water it in. If day 30 falls inside your state's fertilizer blackout, wait for the first allowed date. OVER SOD™ ships spring 2027. About Over Sod 8-0-6
Homeowners and installers are already asking what goes under new sod. Under Sod 4-2-5 is the brand built specifically for that job, blended into the soil. The label method is incorporation. If you cannot mix it in, use the quarter-rate topical application.
Built for beneath the sod.
A 4-2-5, iron-free biological pre-plant fertilizer — named mycorrhizae, beneficial bacteria, Trichoderma, seaweed, and humic acid — at one bag per pallet of sod (500 square feet), which is 50 pounds per 1,000 square feet, blended into the top 4 to 6 inches of soil.