You may also wish to take the time to have a browse through the below site, as it directly relates to lawns in your local area:
I highly recommend you listen to, "You Bet Your Garden" podcast -- Not So Perfect Produce, 27the August 2011 (Direct link to MP3) and start listening at 13mins:27secs in.
How to water your lawn perfectly with Guy Fipps, PhD, P.E., Director of the Irrigation Technology Center at Texas A&M University.
Q. What type of lawn do you have, warm-season or cool-season?
I would guess you have a warm-season lawn, seeing as you're in Texas, but if you could please confirm one-way or the other, and also the type of grass that makes up your lawn, that would be useful to know.
I have Bermuda grass...
Ok! you have a warm-season lawn.
Q. How high do you mow your lawn ie How tall is the grass after you've finished mowing?
Depending on your grass type and the answer given to the above question, you "might" be better served mowing at a higher height.
You haven't yet said how high you mow your lawn, but we do now know you have a warm-season lawn, therefore my recommendations are:
- Early in the growing season (early to mid Spring) as the grass is coming out of Winter dormancy, cut your lawn at 1½ to 2inches (37.5 to 50mm), then from late Spring onward move the cutting height on your lawnmower up, 2inches (50mm) minimum, 2½inches (62.5mm) would be better.
Q. How much water do you give your lawn during each watering?
If you're not sure, do something like the following to measure the amount of water:
- Put a empty, shallow (tuna) can in the middle on the watering zone and measure the depth of the contents after your sprinkling system has turned itself off after 20 minutes.
I give the lawn about 1/3" 3 times a week. I think I'm going to the twice a week at 1/2" you were suggesting.
For a lawn to remain alive (instead of allowing it to go into dormancy) during extreme heat and drought, it needs at least 1inch (25mm) of water per week. The 1inch (25mm) of water is best delivered via either:
One deep watering a week that delivers a minimum of 1inch (25mm).
Or two waterings a week, each one delivering a minimum of ½inch (12.5mm).
Watering a lawn more than twice a week (even during extreme heat & drought) has a negative effect on the lawn ie
It encourages the grass to develop a shallow root system, where as what you really want to do, especially in a situation like yours, is encourage the grass to develop a deep root system, make it go deeper to look for water below the surface.
Frequent watering also increases the possibility of diseases developing in your lawn.
I'm also going to look into adding compost to the lawn this fall. My dad was also saying that I could buy some gardening sand to fill the cracks in. Would you recommend this?
Personally I wouldn't add sand in your particular situation. Why?
Yes, sand is an excellent drainage material and will aid water getting down deep into your soil, but I believe you want to try and close up those cracks and prevent them from returning, therefore I think you would be better served by making the top 12 to 18inches (300 to 450mm) of soil as fertile as possible, thus allowing that soil zone to hold as much water as it can. That said, I would fill those cracks with finely sieved (¼inch/6.25mm) compost (maybe with some gardening sand mixed in) & compost tea.
I would seriously look into improving your soil below your lawn. How?
Below are a couple of things I've done (and continue to do for the most part):
Spread 1inch (25mm) of compost all over the surface of the lawn twice a year.
Once in the Spring - did that for 3 years, stopped doing it this year.
And once in the Autumn (Fall) - have done that the past 3 years and will continue to do it, as part of my Autumn (Fall) lawn care maintenance programme.
Make 5 gallons of compost tea each week (from late Spring to earlier Autumn "Fall") and apply the 5 gallon batch to the front garden one week, then the following week apply a new fresh 5 gallon batch to the back garden. I repeat that cycle for the period given previously. I have been doing this for 2 years now, and without question I have noticed a massive increase in worm activity eg lots of worm castings on the surface of the soil.
The transformation from what I started with, to what I have now, is (almost) unbelievable...
You can read more about my lawn care practices here on SE Gardening. I've now added a few photos to that post, especially take not of the 4 photos labelled "... after 4 weeks of continuous +95°F (35°C) heat, almost zero rain, watered once a week (per above) and not mowed during that time". Maybe last year, but most definitely 2 years ago I would have lost about a ⅓ of the grass in my back garden and would have had cracks in the soil that I could've stuck my fingers down into after going through such an excessive heat period. I'm not saying my lawn and/or soil are now perfect, but without a shadow of a doubt they're improving, getting better each year...
Hopefully with your help my lawn will be the envy of the neighborhood in no time!
Don't expect instant miracles, if you do, I'm afraid you will be somewhat disappointed and may get a little frustrated due to lack of (instant) progress. In reality it's going to take at least a year or two before you see any noticeable improvement, but I guarantee if you do stick with it, you will end up reaping huge! rewards and personal satisfaction from seeing the transformation...
Q. Also, could these cracks potentially cause a foundation issue?
The cracks in the soil won't directly cause any issues with the foundation of your house.
Below are a few things that factor into potential foundation problems when dealing with excessive drying out of the soil:
Depth to underside of foundations.
What type of soil the foundations bear on.
How wide the foundations are ie The bearing area onto the soil.
Excessive drying out of the soil causes the soil to "contract" (shrink), if this occurs to a large enough extent (along with factoring in the above 3 points, plus some I'm sure I've missed) it can possibly cause the foundations to settle.
If after an excessive drying out period, the soil suddenly becomes "super saturated", thus causing the soil to "suddenly" expand, this (along with factoring in the above 3 points, plus some I'm sure I've missed) can possibly result in ground heave that exerts enough upward force to push the foundations up.