Seasonal
How Grass Makes Its Own Food (and Why Timing Your Feeding Matters)
Grass manufactures its own food through photosynthesis and stores energy for the cold months. Understanding this is the key to knowing when to fertilize for a healthy lawn.
May 22, 2026 · 3 min read
To take great care of your lawn, it helps to understand what your grass is actually doing under the surface.
Nature’s solar panels
Photosynthesis is the process of food production for plant life. Nature made grass to manufacture its own food. When conditions are favorable, the green leaves capture energy from the sun and convert water, fertilizer, and other elements into carbohydrates — simple sugars that the grass consumes as food.
During the cool months of the year, grass makes food and stores it away to be used during the warmest and the freezing months, when growing conditions are tougher.
Why this changes when you fertilize
Because your lawn reacts to each season according to soil temperature, the cooler the weather, the safer it is to fertilize. Feeding when the grass is primed to store energy gives you the most benefit.
That’s why we recommend:
- Fertilize with a nitrogen-phosphate-potash combination (e.g. 16-6-8 or 15-15-15) once a year at or around Halloween.
- To go the extra mile, fertilize again with the same product around Presidents Day.
- Important: during summer months, do not apply a nitrogen fertilizer — use only Ferrous Sulfate (Ironite) instead.
The takeaway
Your grass is constantly making and storing its own food. Work with that cycle — feed it when it’s cool and ready to store energy, and back off the nitrogen when it’s hot — and you’ll have a healthier, greener lawn with less effort.
For the full feeding schedule, see our guide on when and how to fertilize your lawn.
Frequently asked questions
- How does grass make its own food?
- Through photosynthesis. When conditions are favorable, the green leaves capture energy from the sun and convert water, fertilizer, and other elements into carbohydrates (simple sugars) that the grass consumes as food.
- When does grass store food for winter?
- During the cool months of the year, grass makes food and stores it away to use during the warmest and the freezing months when growing conditions are harder.
- When is the best time to fertilize based on how grass grows?
- Cooler weather is the safest and most effective time to fertilize — which is why we recommend feeding around Halloween, with a second application around Presidents Day.