About Under Sod
Under Sod 4-2-5 — The First and Only Fertilizer Made to Go Beneath New Sod
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. It is made to go beneath new sod, where freshly cut roots make immediate contact with the nutrients and biology they need to rebuild.
One 25-pound bag per pallet of sod (500 sq ft), 50 lb per 1,000 sq ft, blended into the top 4 to 6 inches of soil.
No rate math. A complete rooting strategy in a single application. Then Over Sod 8-0-6 at day 30.
It's not just a fertilizer. It's a foundation for success.
Our Story
Born From One Question We Couldn't Answer
"What fertilizer do I use for new sod?"
For years, as CT Sod grew and delivered sod across the Northeast, customers kept asking the same thing — and there was no right answer.
Homeowners and landscapers alike didn't know what to use. The few who found something had no idea how much to apply, or whether it would burn the sod they'd just paid for. There simply wasn't a product you could confidently recommend to everyone, with clear instructions and no burn risk when used as directed.
After thousands of orders, we knew there had to be a better way — so we built one.
formulated by Under Sod Brands to our specification.
The better way is Under Sod 4-2-5.
How & Why
Filling The Gap
Traditional starter fertilizers sit on top of the sod, push high-phosphorus top growth, and actually suppress the mycorrhizal partnerships new sod needs to develop deep, resilient roots. Under Sod 4-2-5 takes a different approach: a K-forward, moderate-phosphorus 4-2-5 NPK base — iron-free by design — paired with named endomycorrhizae, a Bacillus and Trichoderma biology package, cold-water seaweed extract, and humic and fulvic acids — the biological foundation new sod actually requires to recover, root faster, and establish into a healthier lawn from day one.