I am starting this thread to pass along knowledge among the community for anyone in my situation: overseeding this fall from Bermuda to Rye. We can discuss all aspects: what type of seed, timing, mowing, and most importantly on here, setting up our Rachio to water appropriately. I am unaware of the differences with overseeding over types of grasses, so I would like to see this thread stick to Bermuda Rye. I encourage anyone to start their own thread for different grass scenarios.
The UofA Cooperative Extension is my current resource. You can find their document here: https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1683-2015.pdf
Timing:
October
30 days before overseeding
o Stop Nitrogen fertilization of Bermuda
14 days before overseeding
o Raise mowing height 30-40% above normal
o Decrease irrigation by 30%
1-3 days before overseeding
o Stop Watering
o Mow at the your orignal height that you’ve done all summer
o Just before overseeding, lower height another 25-30% and leave clippings as mulch for overseed seeds
Day of overseeding
o Use ryegrass seed at 12 to 15lb/1000 sq ft
o Apply ½ of seed walking in one direction, and other half walking perpendicular
7-10 days after overseeding
o Irrigate 3-4 times per day to keep germinated seeds moist
14 days after seeding emergence
o Fertizlie with ammonium phosphate (16-20-0) at 5lb per 1000 sq ft
First mowing
o When ryegrass is ~3” tall
1 Like
@Modawg2k I was hoping someone would start a thread like this. I saw the same document. I’m confused about this part.
You mow at the old height, raise 30-40%, then drop 25-30%. Doesn’t that put you back where you started ?
I’m thinking 4 fixed schedules spaced 6 hours apart, but with what kind of duration. Maybe an inch or two worth of water ?
1 Like
So ready for this thread!
I love all the UofA coop articles they put out (plus I’m partial since UofA is my alma mater), but I haven’t seen this one. This is perfect. New to me that you shouldn’t “scalp” the bermuda. I have always taken it down really low, but based on this document, you should keep some height.
I’ve always had good luck with about 8-10 minutes on my MP-Rotator nozzles and 2-4 minutes on my spray 4-5 times a day spaced out through the daylight hours. I guess it is going to be a bit of a guess, based solely on the moisture level in the first couple inches of soil. Wonder how effectively we will be able to utilize the Rachio moisture graphs to follow this “remotely”.
1 Like
It makes it sound like you start watering that way 7-10 days after, but yeah it should be from day 1.[quote=“azdavidr, post:2, topic:6229”]
You mow at the old height, raise 30-40%, then drop 25-30%. Doesn’t that put you back where you started ?
[/quote]
I will reword. I just copied over from a table in the document and may have typed it incorrectly. 14 days before you are supposed to raise your mower 30-40%. 1-3 days before you mow at your old heigh. Just before seeding, knock it down about 25-30% below your normal original height.
I haven’t even begun to digest the watering part… more to come from my head on this 
1 Like
Good information. But that seeding rate must be a mistake. For rescue the seeding rate is about four pounds per 1,000 square feet and bluegrass is 2-3 pounds per 1,000 square feet. Are you talking annual rye?
Correct me if I’m wrong, but I don’t believe you’ll be able to utilize the moisture graph settings if you use a fixed schedule. I don’t really plan on worrying about soil moisture calculations during the time. I’ve had success at running my system for 5 minutes each zone x 4 each day I see rye growing and then i dial it back. I’ll just manually keep an eye on soil to make sure it’s staying moist. You don’t need a deep watering during this time because the seed is just at the top.
The article just states an application for Rye, it doesn’t specify type. I will say that I do recommend Perennial Rye vs getting the cheaper annual rye. Annual rye produces thicker, less attractive blades and stains pretty easily. The perennial is much nicer and only slightly more expensive.
1 Like
Honestly, don’t know. I’ve haven’t used a fixed schedule yet…but, if you kept the Flex active and added fixed schedules, wouldn’t the zone still calculate moisture level? In theory, the flex schedule wouldn’t ever run since the fixed schedules would keep the moisture level above AD.
If I manually water through Rachio, it calculates it, so I don’t know why adding fixed schedules wouldn’t.
1 Like
Annual is a MESS to mow!!! I think it looks fine if you keep up with it, but I’ll pay the extra for perennial any day.
1 Like
Do any of you lay manure or topper when you seed? I’ve done it both ways, and certainly had better overall growth when using a topper, but it is such a PITA to add that extra step. I see the UofA document doesn’t say anything about a topper, and golf courses never throw anything down…
@tmcgahey I haven’t used topper the last several years and my growth has been fine. I’ve never tried the grass clippings idea mentioned in the article so I’m going to try that. The key is to keep the seed moist, so topper helps with that an preventing drying out… another reason that timing is critical with temperature. I hated doing the topper and vowed to never do it again. I compensate by laying down enough seed
1 Like
What’s your PR and efficiency? That should give a ballpark target for inches applied. Off the top of my head I’ve been thinking 1.5-2 inches would be a good target.
I’m going to run another catch cup test soon since I’ve replaced heads, but mine are looking like this
- 1.35 (65%)
- 2.20 (80%)
- 1.89 ((55%)
One of my friends owns one of the premium landscape companies in Oklahoma City. Besides good soil-seed contact through core aeration, his other secret weapon is a light layer of peat moss. I tried it last year and was impressed.
I oppose overseeding warm season bermudagrass in full sun. It is an absolute waste of water. The practice should be banned in desert regions.
Interesting. That’s about an average of 0.1 inches of water. @tmcagahey uses about 10 mins with MP Rotators, which is what I have now. My PR on those is 0.4, so that would be about 0.05 inches. I would have thought it would be more, but I guess not. Good to know. Thanks to both of you for sharing your info.
When I do an official audit with Irrigation Association methodology and catch cups from Texas A&M I always put out at least 12 catch cups. The goal is to have enough data to get distribution uniformity (DU) from the lower 25 percent then use a run time multiplier to make up for poor uniformity. However before i ever do an audit I firdt do a zone checkup and insist that repairs and adjustments be made. Otherwise the data is useless. Sadly, DU averages only 50 percent on all types of irrigation systems across the United States.
Not good. What changes are you making?
In regards to uniformity?
1 Like
Yes. I look for things like head spacing, mismatched nozzles, high or low water pressure…things like that. I use manufacturer catalogs as a reference a lot
I’m going to run another catch cup test since I haven’t done once since before I fixed some heads. Other that, I don’t see myself doing anything else. I know I won’t be digging up anything to fix any spacing issues. My nozzles are VAN so maybe I’ll mess with how far it throws the water.
