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Garden Help Desk: Tricks of the trade to help decrease weeds

By Usu Extension - | Jun 19, 2021
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Neglected yards are an invitation for weeds. Good lawn care -- deep, infrequent watering, mowing tall, adequate fertilizer and using a mulching mower -- can reduce weed problems.

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A layer of compost over the soil can act as a mulch in garden beds, making it difficult for weed seeds to germinate.

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There are lots of choices when it comes to lettuce varieties, but even heat-tolerant varieties are no match for the extreme heat we've had in June this year.

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Using drip irrigation can reduce the amount of weeding you'll need to do. Weeds can germinate easily where there's moisture, but very few seeds will germinate in the rest of the garden where the surface of the soil is dry

Question: I want to get rid of weeds without using chemicals. I know I can just pull them, but I’d like to do less of that, too.

Answer: Preemergent herbicides can be used to prevent weeds, but they’re not a good fit for every garden or every gardener.

Here are some non-chemical practices for reducing weeds and weeding:

Weed seeds can lie dormant for years until they get the conditions they need for germination — sunshine, favorable temperatures and moisture. If you manipulate those conditions, you can reduce the number of weeds you have to deal with.

Don’t stir up the soil if you can accomplish your garden work another way. Every cubic inch of topsoil is loaded with weed seeds and some of those seeds can lie dormant for years, or even decades, until favorable conditions come along. Disturbing the soil brings fresh seeds up to the sunlight.

Cultivate carefully to reduce the number of weeds that are turned up to the surface of the soil. Hand pull weeds while they are small; you’ll disturb less soil this way. Holding the weeds at their base will help you pull them up, roots and all. Weeding the day after you water will also make hand-pulling easier. If hand-pulling isn’t practical, use a stirrup hoe or circle hoe instead of traditional hoe. Don’t use a tiller to do your weeding; you’ll just be churning more seeds to the surface.

Use drip irrigation for shrub beds and gardens. Weed seeds need some moisture to germinate. Sprinklers will water all the soil in their spray pattern, and all the weed seeds. Drip irrigation waters individual plants but not the soil and weed seeds outside of their drip pattern. Fewer seeds watered equals fewer weed seeds germinating.

Block the sun. Most weed seeds need at least a little sunlight to germinate. A mulch layer of bark nuggets, shredded wood or compost will block light and reduce the number of new weeds you’ll deal with. A one-half- to 1-inch layer of compost is a good choice for vegetable gardens and annual flower beds because it doesn’t need to be removed when you want to plant again the following year. You can turn the compost under, or simply scoot it aside when you want to plant something new. Over time, weed seeds can land on the mulch and germinate, but the weeds will be easy to pull because they’re rooted in the mulch, not the soil.

Prevent weeds from going to seed. In a pinch, you can mow, string trim or “dead head” weeds and then come back to finish later when you have more time. Don’t wait too long; new flowers will appear soon.

What about weeds in your lawn? You’ll do some of the same things –shading the soil and using mulch. Mow tall, 3-3½ inches tall to increase shade on the soil. Apply adequate fertilizer to maintain a dense lawn, but don’t apply more than is recommended. Use a mulching mower to drop the clippings back onto the lawn. The clippings will add a little more shade on the soil.

Water deeply, but as infrequently as your lawn will tolerate. Your lawn is more deeply rooted than any germinating weed seeds will be and can go longer between waterings. The infrequent watering will give your lawn an advantage over the weeds.

There will still be weeds in your lawn, but if you’ll mow tall, drop the clippings and water a little more deeply and less frequently, you’ll reduce the number of new weeds.

Question: My lettuce did pretty good this year, but the lettuce I picked yesterday was already bitter. I planted a heat-tolerant variety, and it was just as bitter as the regular lettuce I tried last year.

Answer: Even heat-tolerant vegetable varieties have their limits, and lettuce is no exception.

Lettuce is a cool season crop. No matter which variety you grow, the quality will be best when it’s grown in cool weather and harvested at its peak. Once summer weather arrives, quality start to decline. You’ll notice the decline first in less heat-tolerant varieties. This year’s extreme heat has been too much, too soon, even for the lettuce varieties that have some heat tolerance.

If you had tasty lettuce earlier this season, give yourself credit for being a successful gardener and repeat that success next year by including heat-tolerant varieties again, planting early and harvesting when your plants are at their peak.


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