I would like to start by congratulating everyone on making through another California and Arizona summer. I know we still have a couple months of triple digit temperatures, but the worst should be behind us at this point. As we move into September our morning temperatures will start to feel less painful, but remember your warm season grass is loving this weather–especially your California and Arizona sod. I have started to field questions regarding fall overseeding and I want to tell you to hit the brakes. Don’t just tap the brakes, slam on the brakes. You will see ryegrass hit the stores in the next week but walk away or buy it and sit on it until temperatures really drop. Today I want to discuss prep for the fall, and how to get your grass ready to overseed. This won’t be a tutorial on how to overseed, but instead some pointers of what to do before you overseed.


Let’s start with why you don’t want to overseed in September. Warm season turfgrasses grow best when temperatures are between 90-105 degrees. The current night time temperature is around 81-84 degrees and we hit 90 most days before 10 am. With temperatures this hot you will struggle to keep any warm season grass in check after you scalp the lawn. Scalping the grass alone will slow it down slightly but adding 3-4 watering cycles a day to your lawn will bring the warm season grass right back. While you can use Plant Growth Regulators (PGR’s) to slow down the growth, these aren’t going to work 100%. Most golf courses and landscape properties have to use these because of timing to open the areas but this is not necessary at your house. You will likely see one of your neighbors out sweating buckets chopping down their lawn over the next couple weeks but don’t get sucked in. Sit back, enjoy the first few weeks of the football season and relax knowing you’re waiting for the right time to scalp your lawn. Their lawn may look better than yours on October 1st, but I guarantee it won’t look better than yours on November 1st.

The first thing you want to do is pick out a date that you will have time to overseed. The entire month of October is a perfect for overseeding. The absolute best time to seed in October is when nighttime temperatures are 55-60 degrees and daytime temperatures are 80-85 degrees. Not only is this best for the grass, its also much more enjoyable to scalp and seed when the sun isn’t beating down on you all day. Once you have picked out your seeding date you can figure out how to maintain your lawn for the next 4-8 weeks. You want to cut off all nitrogen fertilization 30 days prior to overseeding. Having a lush lawn going into overseed will provide you with a headache, a lot of grass clippings, and you will also shock the grass when you scalp it down while its growing. I like to add a fertilizer for the root system at this time of the year. Some examples of products to use would be 0-0-22, 0-0-50, or other products with a good source of potassium and as little nitrogen as possible. You don’t need either one of those bag numbers but a product with potassium (3rd number listed on a fertilizer bag).

The next item we should address is your irrigation. You will want to continue your normal irrigation cycles until two weeks prior to overseeding. During this same window that you switch irrigation times you should also change your mowing height. Let the lawn grow 25% longer than you have been mowing it during the summer months.  Now you can cut the water back by 25-30% and start to make your lawn a little thirsty and slow down the growth rate. You may see a little wilting in between irrigation cycles but there is no need to worry at this time of the year. The longer mowing height will also help you use less water. When you’re a couple days away from overseeding you should turn the water completely off and let the grass dry down. This may take a few days depending on the moisture in the plant.

This is all you need to do for the month if September if you will be overseeding. Please send in your questions (hit the “Ask Jay” button to the top right of the page) and let me know if there is anything I can help you with. Our offices will be carrying perennial ryegrass seed, Soil Burst fertilizer, and sod knives so stop by and see us to pick up your order.

Watch for us out on the football field this season!  We’ve got more fields being played on in NFL and college than any other sod farm.  I am ready for the season!

Until next time,