Effective Methods to Water Your Lawn and Eliminate Spotted Spurge Weed

Effective Methods to Water Your Lawn and Eliminate Spotted Spurge Weed

Summer heat can be really tough to deal with and it’s even more frustrating when you notice the spotted spurge weed in your lawn. Although it may seem like it appears overnight, it actually grows slowly over the summer. By the time you’re ready to give up trying to keep your lawn healthy later in the season, you may notice mature spurge in the dirt patches of your lawn.

However, there is a simple solution to keep spurge at bay: watering deeply and infrequently. You may be used to watering your lawn daily for short periods, but doing it in this way can encourage many weeds, including spurge, to grow. In contrast, watering deeply and infrequently will help your grass develop a deep root system, which will prevent weeds from sprouting in the first place.

When you water deeply and infrequently, your grass will grow denser and fill in any holes where spotted spurge likes to pop up. Over time, this method will prevent the weed from growing at all. Although it can take some time to see results, once your grass develops deep roots, you can count on a happier yard, even when dealing with summer stressors like heat and drought.

Water deeply instead of shallowly and frequently

deep grass roots


Watering deeply is the key to success for a spurge-free lawn. How deep is “deeply?” That may be open to some interpretation, but the University of California recommends watering so that you moisten 6-8 inches of soil. That may seem excessive, but this is where the “infrequently” part comes in. Since you supply so much water, you don’t have to water again until the top several inches of soil is dry.

How long you can wait to water will depend on several factors, like sun exposure, temperatures, and other stressors your lawn may experience. The biggest determining factor is root length. Young grass with shallow roots can’t wait until 6 inches are dry if the roots only reach down to 2 inches. The older your grass is, the longer you can wait because it grows longer roots to reach the water as the soil dries out. Signs that your grass needs water include wilting leaves that develop a greyish-blue tint and lasting footprints. Footprints in lush lawns are normal, and a healthy lawn will spring back into place; however, if those footprints stick around, your grass lacks the moisture to stand up again.

Watering deeply can still be efficient

spurge in lawn

Jean Faucett/Shutterstock

If watering deeply sounds wasteful, there are a few ways you can ensure it stays efficient. Start by practicing this method when your grass is young. Newly planted grass seeds and turf will need to be watered frequently due to their tiny new roots, but once they start to establish, train them to start growing deeper by supplying more water less often. Rather than getting the top inch of soil wet, water the top two, then wait to water when the top inch is dry again. This encourages the roots to grow further down as they search for water. Repeat this process as the growth continues; water 3 inches, then wait until 2 inches are dry.

Spotted spurge thrives in bare patches on your lawn because of all the space it needs to sprawl out its roots. Spurge doesn’t need anything fancy to flourish, so it can grow in compacted soil when your grass can’t. Aerate dirt patches to allow water and roots to pass through easily. As you water your lawn, include any dirt patches. As water enters the soil and grass spreads with long roots, it will prevent patches from forming and outcompete spotted surge.

Dr Heidi Parkes

By Dr Heidi Parkes

Senior Information Extension Officer QLD Dept of Agriculture & Fisheries.