We often see overseeding your warm season California or Arizona sod lawn as a process that should be done in a weekend. For some this may be the most convenient way to prep but for others its okay to take a week or two to complete the process. Trying to knock it all out in one weekend can result in some really long days out in the heat. My suggestion is to slowly start the process now so in a couple weeks when the overseed window opens you’re ready to go and won’t be wasting your entire Saturday on the lawn. Remember that the ideal window is when nighttime temperatures are in the 60’s. We’re currently sitting in the high 70’s so I would expect a couple more weeks. To follow overseed instructions scroll to bottom of this blog.

Prepping for overseed is often a large ordeal, but starting the process gradually can eliminate a lot of headaches. I want to reiterate something I have said for the past few years. The height of the grass is not associated with a quality overseed. In other words, scalping the grass down to the dirt does not guarantee good results, but opening up the turf canopy does. The shorter you mow your lawn the tighter the leaf blades become making it harder to get the ryegrass seed into the plant. If the seed is lying on the surface it will be slow to germinate and much of the seed will be lost. The seed needs a base to grow out of, and getting inside the grass plant allows for perfect moisture, heat, and a solid growing medium. This is why it’s so important to have a good warm season grass base. If you have a new lawn or a weak summer lawn it can have a direct impact on your overseed. The seed will establish much faster inside a healthy grass stand than it will on bare dirt.

Since we’re still a couple weeks out of actually dropping seed let’s discuss initial lawn prep. Now is a great time to let your lawn grow up 25-30% in height to provide more leaf density. Another bonus of maintaining your lawn at a higher height is that it will use less water, and when you scalp your lawn it will leave plenty of healthy new leaves for the spring. If you continue to maintain your grass at its normal height and then scalp it to the ground, you risk injury to your warm season grass for next year. If you have a healthy lawn its good to go through a lightly power rake or verticut the lawn at this time. This opens up the turf canopy and allows seed to get into the ground. If you normally keep your lawn at 1”, you would want to raise the height of your lawn over the next two weeks to around 1.25”. When the weather cooperates, you can then scalp the lawn slightly below your normal mowing height. Most rotary lawn mowers can be lowered to ¾” and this is plenty low to seed into. Keep in mind that the lower you scalp your lawn, the tighter the leaf canopy will be. When the canopy is too tight the seed will lie on the grass surface and a good portion of the seed will not germinate.

As you make your way through the store this weekend you will start to see ryegrass seed all over the shelves. It is extremely important to be vigilant when you pick up a bag of seed. Remember not all seed is created equal. Here are some tips to keep in mind when looking at a bag of seed.

  1. The best material for winter overseed is perennial ryegrass. While it seems like the name annual ryegrass makes sense it does not have the vigor, color, or density of perennial ryegrass.
  2. Lawn areas should be seeded at a rate of 10-12 pounds of seed per 1000 SF. With that being said you may see bags that say this bag covers 10,000 SF. Don’t be confused by the label because much of this seed is sold for use in the Midwest and east coast. They also overseed, but in a much different fashion than we do on the west coast. They are sweetening up their lawns, while we’re essentially putting in a new lawn.
  3. Germination Rate – The germination rate will tell you how much of the seed is viable. If you pick up a bag with a 60% germination rate then you need 40% more seed to put down the correct rate. You want to find a bag with over 85% germination.
  4. Weed Seed – This number should be zero. Any weed seed or inert matter is going to wreak havoc on your overseeded turf.
  5. Often times blended ryegrass seeds are cheaper because they put different grades of seed in the bag. Some blends are very good seed and provide different plant protections, but some mix in lower grade seed. Remember ryegrass seed is priced by germination, weed seed, and quality of the seed. Therefore, if you’ve found a deal on seed, it’s not always your best bet.

Overseeding materials

  1. High quality perennial ryegrass seed. We sell it in our offices starting at $64.99/bag. Availability of seed varieities is different by location.
  2. Starter Fertilizer – When you pick up your seed, also pick up a starter fertilizer. We sell our own starter fertilizer called Soil Burst 4-4-2 that can be applied with the seed or you can pick up 6-20-20, 16-20-0, or 11-52-0 depending on what your stores carry. You can buy the Soil Burst from us online at www.westcoastturf.com or over the phone at 1-888-893-TURF.
  3. Second Fertilizer – If you use the 4-4-2 then this will also work as a second application for the new seed or you can use 21-7-14, 11-52-0, or 6-20-20. These can be applied after you have mowed the grass for the first time.
  4. All of your sprinklers should be working and properly adjusted. Check all of the nozzles after you scalp for any chips or dings that the mower may have caused by cutting shorter.
  5. Power rake or verticutter. These are available at several stores and can be rented for a half or full day.

Overseed Instructions

  1. Cut back your water just enough to keep your summer lawn alive. There is no need to have a lush lawn going into the overseed season. Stop all fertilizer applications 4 weeks prior to seeding.
  2. Raise up the height of your lawn 25-30%. You do this so when you scalp the lawn it is not being mowed down to the dirt, instead you’re scalping to a manageable height for the turf and it will not cause any injury to the turf in the spring.
  3. Power rake or verticut the lawn. Do not set the machine to dig up new rhizomes from the soil. Your goal is to open the turf canopy.
  4. After you power rake mow up the clippings. The lawn mower works really well for picking up the grass. Next set the verticut/dethatcher a touch lower and do the same process in a different direction. This will open up the dense turf canopy and allow the seed to get into the grass plant.
  5. Mow the clippings again. After the clippings have been cleaned up set your mower to ¾” or ½” if you have a reel mower and scalp the lawn. You don’t need to go any lower than this since it’s not about how short the lawn is, it’s about keeping the turf canopy open. The only reason you’re scalping is to keep the warm season grass from competing with the ryegrass seed.
  6. As soon as the lawn is cleaned up you can go ahead and apply your starter fertilizer. I like to use Soil Burst 4-4-2. This is available online at www.westcoastturf.com. If you can’t find the Soil Burst you can use 16-20-0, 6-20-20, or 11-52-0 to get your lawn started.
  7. I like to keep my rocks and edges clean so I use a drop spreader and apply perennial ryegrass at 10 pounds per 1000 SF around the perimeter of the lawn first. I do two passes to ensure the rotary spreader will not throw seed into the rocks. This is not necessary but it will keep the ryegrass from invading undesirable areas all winter.
  8. Next apply your perennial ryegrass with a rotary spreader at 10-12 pounds per 1000 SF to the remainder of the lawn. If you want the best coverage you should apply 5-6 pounds of seed per 1000 SF in two directions. This is always the best approach but again not necessary.
  9. You will have some seed on top of the grass surface but the majority should be inside the grass plant if you prepped your lawn correctly and opened up the canopy. You can use a broom to help any additional seed get into the plant.
  10. Follow watering instructions below

Some people cover their seed with mulch, but you can save your time, money and the smell in your yard because this isn’t necessary. Mulch allows the seed to maintain moisture and keeps the heat in the plant but if you’re seeding in September/October there is plenty of heat. You don’t need to worry about the moisture either. Mulch doesn’t prevent birds from eating your seed and even if they do eat some you have already applied plenty of seed with the 10-12 pound/1000 SF rate. If you live near a golf course you will notice that none of them cover the courses with mulch and the seed comes up really well. It would cost a fortune in labor and material to cover 60+ acres.


Watering your overseed lawn

Week 1-2: 3x daily for 5-7 minutes per cycle. Make sure you don’t have ponding. If you do lower the amount of water. I suggest watering around 8am, noon, and 4pm.

Week 3: 2x daily for 12-15 minutes. Since the plant is very new at this time a morning and afternoon application is best. You can typically mow the lawn for the first time after 14 days. It’s best to let the grass dry down for several hours prior to making the first mow. Keep the mower set at a higher than normal height, do not scalp the grass.

Week 4: 1x per day for 10-15 minutes. During this time frame you can mow every 5-7 days.

Week 5: Every other day 10-15 minutes. Mow your lawn every 5-7 days as needed and make application of Soil Burst 4-4-2, 21-7-14, or 15-15-15.

Week 6 and beyond: Water every 2-3 days as needed until the temperatures cool off for the winter. During the winter you can stretch your ryegrass even longer between watering. I would suggest fertilizer applications every 28 days throughout the fall. When temperatures drop around freezing its best to use liquid fertilizers to maintain turf vigor.

Hit the “Ask Jay” button at the top right of this page if you have any questions.  Try to enjoy some football this weekend, too!

Until next time,