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.
Short answer
Soil test first. If the test reads phosphorus below the lab's establishment threshold, use a true starter such as Jonathan Green Veri-Green 12-18-8 at its label rate, instead of or in addition to Under Sod 4-2-5. If phosphorus is adequate or high, Under Sod 4-2-5 at install and Over Sod 8-0-6 at day 30, as long as your state and local rules allow phosphorus at establishment.
Step one is a soil test
A soil test tells you what the ground under the sod already holds. Pull samples from the top 4 to 6 inches of the area you are about to sod, the same zone Under Sod 4-2-5 is blended into, and send them to your state's land-grant lab. In Connecticut that is the UConn Soil Nutrient Analysis Laboratory, which reports phosphorus as Below Optimum, Optimum, or Above Optimum. Other states' labs use their own bands; read the recommendation printed on your report.
If phosphorus tests below the establishment threshold
Under Sod 4-2-5 puts down 1 pound of phosphate per 1,000 square feet. A soil that tests short may call for more than that at establishment. In that case use a true starter, such as Jonathan Green Veri-Green Starter 12-18-8 at the rate on its label, instead of Under Sod 4-2-5 or in addition to it, and follow the lab's phosphate recommendation for the total. Check the label on the bag in hand: rates differ by product version.
If phosphorus tests adequate or high
Under Sod 4-2-5 at install, blended into the top 4 to 6 inches of soil, then Over Sod 8-0-6 at day 30. Over Sod 8-0-6 carries no phosphate, so the only phosphorus the lawn gets in its first season is the pound per 1,000 square feet that went into the soil before the sod. That fits a soil reading adequate or high only where your state and town allow phosphorus at establishment. A very high reading, a lab recommendation of zero phosphate, or a shoreline or watershed rule can still mean no added phosphorus at all; in those cases follow the lab and the rule, not the bag.
Other times Under Sod 4-2-5 is the wrong tool
- The sod is already down. Under Sod 4-2-5 is built to be blended into the soil before the sod goes down. The label method is incorporation. If you cannot mix it in, use the quarter-rate topical application. After install, Over Sod 8-0-6 still follows at day 30.
- You cannot work the soil. If the site cannot be rototilled or Harley-raked 4 to 6 inches deep, for example over shallow ledge, tree roots you need to keep, or buried utilities, the product cannot go where it is designed to go. The label method is incorporation. If you cannot mix it in, use the quarter-rate topical application.
- Local rules say no phosphorus. Some towns and shoreline buffers restrict phosphorus even at establishment. Check before you buy.
- Seeding, not sodding. Under Sod 4-2-5 is calibrated to pallets of sod. A seeded lawn follows the seed starter's label.
Where this applies
The same soil-test-first rule applies in every state guide: Connecticut, Massachusetts, Rhode Island, New York, Long Island, New Jersey, Pennsylvania, Maine, New Hampshire, Vermont, and the Pacific Northwest. See the Under Sod 4-2-5 product page for the full analysis and Over Sod 8-0-6 for the day-30 step.
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.