As winter draws to a close, it is time to think of spring maintenance tasks to get the lawn off to a good start for the year. The first application of pre-emergent herbicides should be completed before soil temperatures reach 50 degrees Fahrenheit. After that, core aeration will take care of compaction in the soil, and make later applications of herbicide and fertilizer more effective. Post-emergent herbicides and lawn fertilizers can be applied in late March through April to help the lawn grass green-up without competition from weeds.
Aeration
Annual aeration completed prior to the first spring fertilization is a key step in maintaining a healthy lawn. The best equipment for this task is a core aerator, which removes plugs of soil and deposits the removed cores on the surface of the lawn. This corrects the problem of soil compaction and allows water, nutrients, and oxygen to reach the grass roots. Do not use equipment designed for spiking a lawn, which increases the soil compaction.
Aerate about 24 hours after a light rain shower or normal watering, so that the soil is not bone-dry. Choose a day when the temperature is not too high, such as in the early to mid spring. Cores should be left on the lawn to decompose and return nutrients to the soil. They will disappear in about two weeks. Aeration will stir up weed seeds, which can be stopped from growing by applying a pre-emergent herbicide after aeration.
Herbicides
Different types of herbicides are designed to kill weeds in different ways. Pre-emergent herbicides prevent weeds seeds from sprouting and are commonly used on annual weeds like crabgrass. Post-emergent herbicides will kill weeds that are already growing, including perennial weeds like dandelions.
Between now and March 15th is the best time to apply pre-emergent herbicides in Texas. Most pre-emergent products should be watered-in after applying over the lawn. Do not use pre-emergents on newly seeded lawn or areas that will be seeded within the next few months, since they will prevent grass seed from growing.
Between March 15th and May 1st, apply a post-emergent herbicide to get rid of new weeds that escaped the initial herbicide application. A product containing both pre-emergent and post-emergent herbicides can be used after aeration to prevent newly stirred-up seeds from germinating and to eliminate weeds that are currently growing.
Fertilizer
The first application of fertilizer can be applied at the same time as the second round of herbicide, between March 15th and May 1st. Fertilizing a day or two after aeration is ideal, because the holes in the soil will let nutrients reach grass roots quickly. Weed ‘n feed products, which combines lawn fertilizer and weed control, are designed for this use. However, they may result in uneven or excessive applications of herbicide. To better control dosage, apply fertilizer and herbicides separately.
The best equipment for applying dry fertilizers is a drop or rotary spreader. These can be set according to the label instructions to evenly dispense fertilizer over the lawn. Walk the spreader around the edges of the lawn, then cover the remainder of the lawn in both directions to evenly distribute the fertilizer. Liquid fertilizer can be applied using a sprayer or, in some cases, by attaching the product to a garden hose.
