A lawn that was deep green in May can turn pale by July. The color goes flat and yellow-green, and the newest growth looks the palest. Many homeowners turn the water up, and a week later the lawn looks the same or worse. In Cache Valley, this color change usually starts in the soil. Before you add water or nitrogen, raise your mowing height and get a soil test.
A pale lawn is not a dry lawn
A dry lawn turns blue-gray. Your footprints stay pressed into the grass, and the blades fold in on themselves. A lawn short on iron turns an even yellow-green. The grass is moist and still growing, and the newest blades at the top are the palest.
Extra water will not fix an iron problem. In July heat, frequent watering keeps roots near the surface and invites disease. A lawn with shallow roots has a harder time getting through August.
High pH often locks the iron away from the roots
Cache Valley soils are alkaline and calcareous. Alkaline means the soil has a high pH, and calcareous means the soil is rich in lime. Most of our soils hold plenty of iron. At a high pH, alkaline soil often locks that iron into forms that grass roots cannot absorb. The iron is like food in a locked pantry. It is in the house, but the grass cannot get to it. We do not try to open the pantry by lowering your soil's pH. We apply iron to the leaf so the grass gets it without the soil.
Grass needs iron to make chlorophyll. Chlorophyll is the pigment that makes a leaf green. A lawn that cannot pull iron from the soil makes less chlorophyll and turns pale even when you feed and water it.
More nitrogen does not bring the color back
Many people reach for another round of weed-and-feed that is heavy in nitrogen. Nitrogen greens a lawn that is hungry for it. In July a pale lawn here usually has enough nitrogen. Kentucky bluegrass that is pushed to grow fast in July heat puts out thin, soft blades. Those blades scorch easily and pick up disease. Heavy feeding also does nothing to free the iron in the soil.
Liquid iron applied to the leaf in June
In June we apply liquid iron to the grass along with a 15-0-15 fertilizer. The leaves take the iron in before the soil can lock it up. The numbers 15-0-15 mean 15% nitrogen, 0% phosphate and 15% potash. Potash is the form of potassium on a fertilizer bag.
If your lawn is on one of our programs, we send soil cores from your lawn to a soil lab each September. The pH reading on your soil report tells us how likely your soil is to lock up iron. You get a copy of the report.
One application of liquid iron greens the grass for several weeks. Complete Lawn and Pest repeats the iron at every feeding visit for that reason. Since your soil stays alkaline, expect the lawn to need iron again next summer. We skip July because the June feed and iron carry the lawn through the heat. In August we feed again and treat the whole lawn for weeds a second time.
What you can do this week
- Raise your mowing height. Longer blades shade the soil and hold moisture. Taller grass also grows deeper roots.
- Water less often and for longer. A few long soakings send roots deeper than a light sprinkle each day. Run the water before sunrise to cut evaporation and disease.
- Hold off on heavy nitrogen. Save the heavier feeding for fall.
- Get a soil test. The soil report shows your pH. A high number tells you iron is the likely reason your lawn has gone pale.
If your lawn has gone pale, request a free assessment. The visit takes about 20 minutes. We measure your lawn and give you a price for each program before we leave.