What’s the Best Time to Spray Dandelions? When is it Too Late?

Dandelions are hard and challenging to control.  A right spraying timing is all you need to manage and keep your lawn free of dandelions. Wrong timing, and you will have to deal with them all through the growing season. So, let’s see what the best timing to spray dandelion is and when it is too late.

The best timing to spray dandelions is in fall and before seed germination. In the fall, dandelions shed off their leaves to conserve water and sugars for the winter. Thus, spraying dandelions in the fall, the herbicide will be taken to the roots alongside the sugars to kill the roots effectively.

Another right time is spraying the lawn before the seeds germinate. Or, when the dandelions are young – around two weeks – with one or two leaves. Young dandelions respond so well to herbicides.

It will be too late to spray dandelions in the winter and in the spring. In the winter, dandelions are dormant and spraying them at this time it will be useless. In the spring after the regrowth, it will be difficult to kills the well-rooted dandelions.

Dandelions have deep tap roots about 8-16 inches below the surface ground. Thus, the essence of the right timing spraying is to kill the deep roots or prevent the seeds from germination.

When do dandelions grow?

Dandelions grow from either seed germination or bud crowns that form on the upper part of the roots. When they grow depends on if they are growing from seeds or buds.

Dandelions from seed germination: dandelion achene seeds germinate all through the growing season. They germinate faster in moist soils and optimum temperatures of about 77oF. The seeds germinate faster in fields with exposure to enough sunlight. And, the germination is slow in cold temperatures. The seedling process takes 2 to 4 months, depending on soil conditions, light, and temperature.

Dandelions from buds: In the fall, dandelions shed off their leaves to conserve water and sugars for the winter. The weed plants remain dormant all through the winter season. In spring, small buds appear on the upper part of the roots. The buds grow into new weed plants.

What’s the best timing to spray dandelions with herbicide?

The best time to spray dandelions with herbicide is in the fall. It is economical to spray dandelions in the fall when most weed seeds are germinating. In the fall, dandelions shed off their leaves to conserve water and sugars. At this time, dandelions transfer their sugars from the leaves to the roots for winter storage.

So, spraying at this time, the herbicide will infiltrate down to the roots alongside the sugars. The herbicide will then destroy the long taproots leading to the death of dandelions.

Spraying dandelions in the fall make the garden safe for the incoming crops. In spring, plants will grow healthy and robust with no competition with the weeds. Also, there will be no chances of harming the crops with herbicides as there will be no weeds to spray.

When is it too late to spray dandelions?

Spraying dandelions towards the end of fall and in the winter will be too late. Dandelions shed off their leaves in the fall to conserve water and sugars for the winter season. Therefore, in the winter, there will be no leaves to spray. In spring, buds grow on the upper part of the roots. The bud crowns regenerate into new growth of dandelions.

Should I spray the dandelion killer before or after mowing?

You can spray the dandelion killer either before or after mowing. There are two significant herbicides that you can spray either before or after mowing. That is:

  • Pre-emergent dandelion killers
  • Post-emergent dandelion killers

Pre-emergent dandelion killers

Pre-emergent dandelion killers disrupt the germination and growing process of weed seeds. Apply your pre-emergent dandelion killers after mowing and water the lawn for about 3 weeks. Here is the procedure for applying pre-emergent herbicides:

  1. Choose either granular or liquid pre-emergent herbicides.
  2. Apply the herbicide into the lawn surface.
  3. Water the lawn for around three weeks to activate the ingredients of the herbicides.
  4. Apply pre-emergent herbicides either in the winter or fall. This is to hinder the germination of dandelion seeds.
  5. Always pre-emergent before the dandelions start growing. Once they grow, it will be useless to use pre-emergent dandelion killers.

Post-emergent dandelion killers

Apply post-emergent dandelion killers before mowing. Post-emergent dandelion killer already existing weeds. There are two categories of post-emergent herbicides:

  • Selective herbicides: these only kills the dandelions.
  • Non-selective herbicides: they non-selectively kill all the plants that they land on.

Here is the procedure:

  1. Choose either liquid or granular post-emergent herbicides.
  2. Apply before mowing when dandelions start growing.
  3. Using dandelion killer chemicals saturate the soil, especially at the base of the dandelion.
  4. Spray well all the exposed parts of the dandelions. Avoid leaving patches with dandelions that may lead to regrowth and redistribution of the obnoxious weed.

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