January is still too early to determine proper timing for application of pre-emergent weedkiller granules (except in deep South Texas, where that timing is already here).
• The weeds you’re seeing out in your lawn right now are almost all annual weeds.
Grass burs and Crabgrass Prevention begins two weeks prior to average date of last killing freeze.
For the weeds you can see now… Those are cool-season weeds that germinate in fall, so that application must be made the last week of August through the first week of September. Dimension, Halts or Balan for grassy weeds. Gallery for broad leafed weeds.
For the weeds that will germinate as it gets warmer… In most parts of Texas we are worried mainly about crabgrass and grass burs. Those are summer weeds. Your first application needs to be about two weeks before the average date of your last killing freeze in your area. Learn that date and commit it to memory, because it’s one that will keep coming up for many gardening tasks. For those grassy weeds, apply Dimension, Halts or Balan.
Repeat the spring application 90 days later… These pre-emergents have a 100-day effective life, so you’ll need a booster shot three months after the first application. That will give you a full season of prevention against crabgrass and grass burs. We usually don’t have enough broad leafed weeds in the summer to justify the expense of Gallery granules
• Broad leafed (non-grassy) weeds can be treated with appropriate broad leafed herbicide. Read and follow label directions carefully.
• Horticultural (dormant) oil spray to reduce populations of scales and overwintering insects.
• Have frost cloth handy to cover annual flowers and vegetables, also flowering shrubs should freezing weather return.