No matter how many years I live in Arizona it always surprises me how quickly the temperature goes from 50 degrees to 90 degrees. I can’t say that I’m very excited to see our first 90 degree day this coming weekend. I would be okay if we could make it until April for this to happen but we don’t get that choice. Since we rarely have a winter in Southern California and Arizona February is the month to apply your pre-emergent herbicide to control summer annuals. If you’re from back east or the mid-west you will realize this is about three months earlier than you would apply one but timing is everything in turfgrass. I spend so much time discussing weather in these blogs because every part of the grass cycle is controlled by temperature.

Summer annual weeds can be everything from spurge to any number of broadleaf weeds. These weeds attack weak areas of your lawn and fill in voids because of the lack of competition with your grass. There are a few options to controlling these and the first is to maintain a healthy balanced lawn. The second is to apply pre-emergent fertilizers, and the third is to treat weeds that pop up with post-emergent herbicides or by hand picking them.

Most people don’t want to deal with an invasion of weeds in their lawn so the easiest and most efficient way is to apply a pre-emergent herbicide. One thing you must keep in mind when you apply these is that they won’t control weeds that are already present but they will help prevent new weeds from emerging from the ground. When you’re looking at different herbicides to apply you need to carefully inspect the label and see if the product is okay for overseeded turf, non-overseeded turf or both. Most of the herbicides are okay for both but different rates will be listed on the label.

Many homeowners would rather avoid using herbicides on their lawn which leaves a couple of options. The first is to apply corn gluten which works inhibits weed seeds from rooting into the ground. Corn gluten will control a number of weeds but you may not see the same results you would with a pre-emergent herbicide. Often times if you use corn gluten you will have a few weeds here and there break through the barrier so hand picking them will be necessary. If your lawn is healthy and null of any voids the corn gluten should help keep most weeds from invading your turf.


Pre-Emergent Weed Control

Here is a small list of some of the more popular pre-emergent’s on the market for bermudagrass and paspalum and they can be picked up at most specialty stores and used safely. Some of these do require a certified applicator to apply so you may want to contact a weed company to apply them for you. You will not be able to purchase the restricted use pesticides without a license. Many stores will carry their own generic brand of these chemicals but make sure you are getting the same active ingredient. If you cannot find one of these products in the store most of them are available online to ship to your door. Herbicides are generally not cheap but they are effective when used right so make sure you do some research.

• Barricade 65WG (Prodiamine)
• Dimension (dithiopyr)
• Ronstar (oxadiazon)
• Pendulum (pendimethalin)

Before making an application of a pre-emergent herbicide it is important to follow the proper steps and always read the label.

• After you apply the herbicide, irrigate your lawn to activate the chemical.
• Measure your lawn surface area and calibrate your spreader properly.
• Do not over apply an herbicide hoping for better results.
• Some products allow for a second application. Read the label first!
• Newly installed lawns (within 90 days) should not use a pre-emergent.

For those of you that would rather wait for the weeds to appear and spot treat them you can find many post-emergent herbicides that will work in your lawn. These applications vary in effectiveness based on the maturity of the weed. I prefer to use a pre-emergent but either approach will work. Keep in mind that some weeds such as crabgrass and poa annua are very tough to control once they emerge from the soil. They do make chemicals to treat both but they are very expensive. Most of these chemicals cannot be applied to ryegrass so you would have to wait for the spring transition (April/May) before spraying your lawn.


Fertilizer Recommendations

The air and soil temperatures are now warm enough to switch from foliar to granular fertilizers. It is okay to still spray your lawn once a month with foliar fertilizers but if it is easier for you to apply a granular now is a good time to do so. Most pre-emergent contain some fertilizer in the bag but you can buy some that don’t have any. For most people it is easier to apply one product but if you can’t find a product with fertilizer go ahead and make a second application. At this time of the year you will be very successful with any of the following products.
• Soil Burst granular 5-15-10 or any of the foliar products
• Calcium Nitrate 15.5-0-0
• Turf Royale 21-7-14
• Ammonium Phosphate 11-52-0
You should always water in your fertilizer with 15-20 minutes of water so it completely breaks down and the plant can take up the nutrients.


Water Recommendations

Every lawn and irrigation system will vary in the length of time they need to be ran but you’re looking to water to a 6-8 inch depth. This can be checked with a screwdriver. If you can easily push it down 6-8 inches then your lawn is getting plenty of water. If it can’t penetrate the soil you will need to run more water. Soil compaction can be a real problem with our clay soils so if you can’t get a good watering without run off it is important to have your lawn aerated. This will allow for better infiltration and percolation.
Overseeded lawns should be watered no more than 3 days per week and non-overseeded lawns no more than once every other week until March. In March you can switch to once a week and then by April to a couple days a week. There is no point in wasting water on dormant turf that will not green up until late march when the soil temperature is warm enough.


New Lawn

Since we live in such a temperate climate sod can be installed year round. There is no bad time of the year to install a lawn. If you’re not sure what type of lawn interests you simply call one of our representatives and they will help you choose the perfect grass for your area.

Until next time, Jay