The first thing to do when you have large patches and clumps of chickweed is to pull as much of it out of the ground. Solarization is also the best method. If solarization is done in late summer and the soil is not disturbed, subsequent winter crops can develop a canopy and become more competitive before other winter weeds germinated.
If you only have a small infestation, you should be able to control the chickweed simply by using weed killer on your yard. If you have large clumps of chickweed in your yard, first you need to pull as much out by hand as possible. Then aerate the ground with a shovel. Fertilize and then water daily.
You should dig the soil regularly and put fertilizer into the soil to keep it light to work with. Go round the garden once a week pulling out any weeds that grow. Using a weedkiller at intervals making sure that when applying it is in dry conditions, most weedkillers need eight hours without rain to successfully kill weeds.
Pull as much of it out of the ground as possible. Make sure you get the root of the plant. Get a herbacide with glyphosphate. Apply the herbacide carefully and sparingly as it will kill other plants as well. You can also cover the chickweed with ammonium sulfate early in the morning while it is still damp from the dew.
Pull out the reprehensible chemical big guns without a thought, eh? Google corn gluten for a organic, non-toxic, effective method of control. Not easy to find in big boxes but it is out there.
