How Fast do TTTF Roots Grow?

10 years ago

Apologies if this has been answered before, but I couldn't find the answer I was looking for. I'm trying to find out how many inches per year TTTF roots typically grow. You hear about grass roots going down two, three, even four feet, but I'm assuming this happens over time. Of course any answer will depend on such things as type of soil, amount of compaction, watering rate, etc., but just a general idea, if that's possible. For example, if I plant new seed this fall, about how deep would the roots be by next spring? I'm wondering if they would be deep enough to survive the recommended "deep and infrequent" watering schedule of once or twice a week, or whether they would need more frequent watering to make it through that first summer, and then by the second (or third?) summer, they would be deep enough to stretch the watering interval.

Reason I'm asking is that I killed off my mostly weedy lawn last fall and reseeded. It looked pretty nice after a few weeks, made it through the winter, and still looked nice going into summer. When it started heating up, I supplemented any rain we got, giving it about an inch per week, but making sure that it was infrequent, trying to encourage those roots go grow deeper. But the lawn kind of died dramatically in the middle of summer. I thought it was perhaps brown patch and put down a fungicide, thinking it would green back up, but no. It was dead. Now I'm thinking it was a simple lack of water. Even though they were getting an inch per week, maybe those less-than-one-year-old roots just weren't deep enough yet to benefit from "deep and infrequent". Should the "deep and infrequent" advice have a caveat that it is only for established turf, and that new growth needs a couple years before that applies?

Sorry if this is common knowledge and I'm a big dummy, but I was just trying to do the right thing, honest officer!

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Comments (6)

User
10 years ago
last modified: 10 years ago
While tall fescue roots CAN go as deep as 36", root growth is proportional to the amount of top growth. If you let the grass get tall (say 18-24"), you may very well get roots that deep. However, in a home lawn scenario where mowing occurs frequently, 8-12 inches is probably as deep as they're going to get, and that's the optimistic estimate after a few years. Typically, you see 6-8 inches.

A couple of things about watering.
- I recommend watering when grass shows signs of drought stress rather than by set interval. This insures you go as long as possible between watering while taking all variables into consideration : temperature, soil type, grass age etc. If it's showing drought stress, it's time to water, whether you last watered 3 days ago or a month ago. More info here
- Summer is not a time for root growth for cool season grasses. Once soil temps hit 77, root growth ceases. Encourage root growth in the fall and spring, and work towards keeping the grass alive during summer. What I mean by that is, making the grass suffer in hopes of root growth is useless. If it shows signs of drought stress after 3 days, water. See above.
In regards to your grass dying, it may have very well been fungus. We don't know. But once killed by fungus, fungicide will not bring it back, it will just prevent further damage to grass that's still alive. If you live in the transition zone, you should seriously consider a preventive fungicide program starting May.
headmotty
Original Author
10 years ago
OK, thanks. I do admit I could have paid more attention to signs of stress. So since you say that 6-8" root depth is typical, and that's "after a few years", I guess they wouldn't be at that depth after only 9 months (from seeding in September through the following June), correct? Would they only be something like 2" or so by the first summer?
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User
10 years ago
They may very well be about 4"-6" deep with proper watering. They could also be 1" -2" deep with poor watering. Take out a soil plug and inspect the roots to know for sure.
headmotty
Original Author
10 years ago
Check. At any rate, I reseeded a week ago, and am getting nice germination. I'll be more vigilant next summer and water at first signs of stress. Thanks for the knowledge!
User
10 years ago
If you're looking to enhance root development, I would recommend looking into spraying a PGR through fall and summer.
headmotty
Original Author
10 years ago
Well, I really don't want to get sucked too deep into this lawn care vortex. I'm busy enough as it is to add yet more rounds of whatever application to the lawn. I don't need the best on the block, just something pretty decent without huge bare spots, and it's ok to have a certain amount of weeds or whatever mixed in. But appreciate the advice...