Cold temperatures have arrived in California and Arizona, and those of you with overseeded sod may begin to see your lawn go in a little shock. One of the things you will notice first is bermudagrass going dormant in the turf causing small quarter sized yellow spots in your lawn. This is nothing to be concerned about as today we will discuss getting those spots to fill in. If you didn’t overseed your lawn for the winter it’s most likely dormant at this point and you can sit back and let your lawn sleep for a few months.

I’m sure many of you have seen the small yellow spots over the years in your overseeded lawn. The question is what is causing it and what can you do about it? First, this isn’t something to be concerned about. It’s actually a sign that you had a very healthy lawn going into the overseed season. Since many people overseed in late September/early October you’re still fighting with warm season growth. By supplying water and fertilizer to overseed the bermudagrass continues to grow and has a tendency to out compete your newly seeded ryegrass. When you’re overseeded lawn first start growing it looks immaculate, but it’s good to remember some of this is bermudagrass. The bermudagrass/ryegrass combination looks incredible and when it’s growing in it can be tough to distinguish the two.

When bermudagrass fades into winter dormancy your overseeded lawn often develops small spots indicating where it was growing faster than your rye seed. So what do you do now? Most granular fertilizers are slow to get a reaction during cold nights so I suggest switching to a foliar (spray) program during this time period. There are several fertilizers you can use with good success.

Ferrous sulfate (iron source) – ½ pound per 1000 SF of lawn. This product will stain all sidewalks, concrete, pavers, etc so keep a border if you will be spraying it. Ferrous sulfate heats up the plant to help it grow during cooler times of the year.

Calcium nitrate – This provides the grass with both nitrogen and calcium without sulfates. Calcium needs to be continuously supplied to the plant during the growing season since it’s not mobile in the plant. This issue with calcium is it takes a long time to be absorbed so a readily available source like calcium nitrate improves calcium uptake. I don’t recommend applying this with ferrous sulfate. Keep this to a single source application.

Soil Burst 4-0-6 – This is a granular fertilizer but is an organic slow release fertilizer that will work wonders in the soil. This product will provide your soil and organisms in the soil with food during the cold temperatures. This is a great starter fertilizer to be applied prior to installing any lawn.

Organic fertilizer sprays – Similar to the Soil Burst 4-0-6 you can buy a host of different organic spray formulations. Organic fertilizers maintain organic matter, feed organisms in the soil, and help with uptake of the plant. Some products that will give you success are seaweed extracts, compost teas, kelp, etc. These can be foliar applied and taken up through the roots and leaf.

I could name hundreds of products but the goal here is to keep it simple with some products that are readily available to every one of you.

Endurant turf paint – This product can be applied to overseeded or dormant turf to give your lawn the same ryegrass color you seeded with. The turf paint serves another purpose besides just providing color. It heats up the plant and will allow for faster spring green up in dormant turf and will help new ryegrass plants fill in any voids from the encroaching bermudagrass during seeding.

Watering during the winter

If you haven’t dramatically cut back your water for the winter I suggest going out today and adjusting your clock. A winter ryegrass lawn needs no more than 20 minutes of water 2-3x a week during December, January, and into mid-February. If you didn’t overseed your lawn I suggest one application of water a month for the next three months unless we get good rainfall. If it rains be sure to turn your clock off and wait for the lawn to show signs of stress. Remember you don’t need to water a lawn just to water. Be water smart and wait to see a little bluish/grey tint to the leaf before making your next water application.

If you have any questions, please hit the “Ask Jay” button at the top right of this page, and I will be happy to help.

I hope you are gearing up for a great holiday season and Bowl Game time!

Jay