Mike offers advice on reclaiming areas that have been taken over by weeds, in particular weeds that have set seed. How to Cut Weeds After Seed Heads Appear. Weeds reproduce rapidly when they grow seed heads, and they can become an eyesore quickly as well as rob your garden and lawn of vital nutrients. Seed heads contain mature seeds that typically are spread by wind and insects. Ideally, weeds are removed before the appearance of … Weeds in your garden are not only unsightly, they also are the source for more weeds to invade. Prevent new weeds from growing with Preen Weed Preventers. – Preen
Controlling Weeds That Have Gone to Seed
Q. I’m looking for advice on how to get an area of my garden back under control without using chemicals . I failed to keep up with the weeding in a section of my vegetable garden that is about fifteen by 30 feet. It had crabgrass, clover and a few other weeds that went to seed. I ripped them all out as best I could, but can’t get all the roots out—and I can see that a lot of seed has scattered on the surface of the soil. I wonder if covering the area with impermeable black plastic until next May would kill everything? Or maybe it makes things worse by keeping the area warm enough for the weeds to survive the winter?
—Kat in Leesburg Virginia
A. Let’s start with the black plastic idea.
Wishful thinking. Weeds need no help surviving winter; and only clear plastic stretched tight over a perfectly prepared area for an entire summer can kill weed seeds. It’s called ‘soil solarization’, and this description of the proper technique is not my opinion; it’s the only way that diligent researchers got it to work. (Here’s the details in a very popular previous Q of the Week .)
Her best bet now is to use a ‘flame weeder’—a hand-held, propane-powered garden torch that shoots a small flame out the business end of a long shepherd’s hook-like wand—to slowly toast one small section of the infested area at a time, preferably on a hot day when that soil is bone dry. It’s much less work, you get to stay upright while you deactivate those weed seeds, and every little ‘pop’ you hear is an emotionally satisfying sign that you’re doing it right.
(I’ve always been emotionally satisfied by my flame weeders. [Mom said it was OK to be easy; just not cheap.])
So–what about those roots still in the ground?
It sounds like Kat had a typical round of frantic but useless pulling. I suggest she let those roots re-sprout, and when they’re tall enough, soak the soil thoroughly and pull gently at their base. (Be sure to compost those pulled roots with lots of soil still attached; they’re full of nutrients, and they’re the perfect ‘green material’ to mix with shredded fall leaves. And the attached soil contains lots of microbial life to get that compost cooking!)
In general, this is the best way to handle weeds of almost any size: wait until right after a heavy rain or soak the soil for hours—really saturate it—and then pull ‘low and slow’; get down to where the plant meets the soil and pull slooowly and gently. That’s how you get the roots out the first time.
‘Angry yanking’ may seem emotionally satisfying, but it doesn’t get the job done. And it tends to be the panicked tactic of choice for large areas that seem insurmountable. Better to slow down and spread the job out over a week or so. An hour a day of doing it right in small area after small area gets rid of the weeds without you needing a corner man.
Now: why did I say ‘weeds of almost any size’?
Because, as Kat discovered, yanking weeds that have already gone to seed spreads the seeds. When weeds are seedy, don’t pull right away. Instead use that flame weeder to incinerate the tops of the plants. Then run the flame up and down the sides of the plants; wherever you see seed pods. The torch will toast those seeds, and you can then pull out the plants without planting next year’s crop of weeds. Bonus: Many weed seeds look like Munchkin fireworks when they pop!
(Yes, the words ‘easily amused’ do come to mind; saves me a fortune on my cable bill.)
Anyway; next season, delay planting these areas until any missed weed seeds have germinated and been growing for two weeks. Then carefully and methodically slice them off at the soil line with a hoe that has a flat super-sharp blade, like a diamond hoe—creating what’s known as a ‘stale seed bed’. And whatever you do, don’t till the soil; tilling plants weed seeds!
An alternative tactic would be to use the natural pre-emergent herbicide, corn gluten meal . Just as you would do with cool-season lawns, applying corn gluten meal at the rate of twenty pounds per thousand square feet in the Spring (when forsythia and redbud just begin to bloom or when the soil temp reaches 55 degrees F. measured four inches down) would prevent a lot of dormant weed seeds from sprouting. Heck—because those seeds are on the surface, ‘CGM’ might provide astounding control. (Be sure to apply as per package directions.)
Now—that would also put a lot of Nitrogen into the soil, so I would then use that area to grow a non-fruiting, but Nitrogen-hungry crop like sweet corn , field corn, popcorn, salad greens, potatoes, onions or other things I’m not thinking of right now.
Corn of any kind would be especially ideal; ‘maize’ loves a Nitrogen-rich soil, and 15 by 30 would be a perfect size to seed a big patch and get lots of nice full ears. (I personally vote for popcorn—super-fun to grow!~) You just have to wait six weeks after applying the CGM or pre-sprout the corn seeds, which I recommend anyway. (You’ll find those pre-sprouting details under C for corn [maybe] and under P for peas [definitely].)
In addition, the way she describes this area, we have to assume that it’s a flat earth garden; a design—or lack of design—that guarantees maximum weed woes. You get a lot more eatin’ with a lot less weedin’ from raised beds . Four by eight is the ideal size for each bed, with two-foot-wide walking lanes in between. Because you build the growing area up to a foot above the soil line, grassy weeds like the clover and crabgrass she specifically names can’t migrate in from the outside. And you can just mow the actual lanes to keep their weeds under control—no pulling.
And the cool air of fall is perfect for getting outside and doing some raised bed building! And if you build those beds now, they’ll be ready to plants in the Spring. Hint; hint….
Final note: But if Kat does take the ‘corn gluten meal followed by some kind of corn’ advice, she should build those raised beds in other areas of her garden. Corn is one of the few crops that does better in flat earth than raised beds. Sounds like a plan!
How to Cut Weeds After Seed Heads Appear
Weeds reproduce rapidly when they grow seed heads, and they can become an eyesore quickly as well as rob your garden and lawn of vital nutrients. Seed heads contain mature seeds that typically are spread by wind and insects. Ideally, weeds are removed before the appearance of their flowers that eventually release seeds. If some of them escape removal before they produce seed heads, they can be cut down. When you remove weeds with seed heads, you eliminate one of the biggest sources of weeds on your property.
Cut off weed flowers and seed heads using pruning shears, and dispose of them immediately. Cutting the flowers and seed heads rather than removing entire weed plants is ideal if you find weeds in your vegetable garden and don’t want to disturb your crops by yanking out whole weed plants. If the weeds contain large leaves that cover your plants, clip off all the weeds’ foliage so your crops receive more sunlight.
Cut weed plants to ground level with pruning shears or a lawnmower that has a mower bag. If you use a lawnmower, empty its mower bag into the trash immediately so that you do not inadvertently spread the weed seeds the next time you use the lawnmower.
Collect all of the cut weeds and seed heads with a rake, and dispose of them. Repeat the cutting process when the weeds grow and especially before they produce seed heads again.
Weeds Gone To Seed
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Why You Should Never Let a Weed Go to Seed
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A big reason that weeds are such effective invaders is that most of them are very prolific seeders. It’s not unusual for a single weed plant to throw off hundreds of viable seeds. If weeds are left to grow and produce new seeds, any that fall to the ground can live for years in the soil. Some can live for decades. That’s why the number one rule in winning the long-term battle against weeds is to stop them from growing at all.
Dealing with weeds you already have
If common spring-time sprouters like chickweed, purple deadnettle, dandelions, garlic mustard, and creeping speedwell have already flowered, a steady supply of summer weeds will be attempting to flower and set seed. Some of the worst summer seeding weeds include pigweed, purslane, thistle, lamb’s quarter, black medic, spurge, bindweed, Japanese knotweed, and assorted grassy weeds.
Pulling and/or digging is the most immediate, effective control. Just be sure to get roots and all or else many weeds will simply sprout new leaves from the roots left behind.
Be persistent, and you’ll eventually win – or at least gradually reduce the outbreaks by denying weeds from reproducing via seeds. Even if you can’t pull or kill all existing weeds, at least patrol enough to cut, hoe, or weed-whack any that are forming flowers or flower stalks.
Preventing future trouble
Bare soil only invites weeds, so it is best to add plants to bare spaces and add a few inches of mulch to your landscape beds to fill the space, leaving no room left for weeds.
Granular weed preventers such as Preen can go on top of mulched, planted beds to further stop new weeds before they have a chance to sprout and grow. Two to three applications per year can give season-long protection, depending on your climate and which type of Preen you use.
Preen offers many different options for controlling weeds in your landscape.
provides protection from new weeds for up to 6 months and is labeled for use around 600 plants in perennial flower beds; around groundcovers, trees, and shrubs; and in xeriscape settings and rock gardens. blocks new weeds from germinating in your garden for up to 3 months and is labeled for use around 200 established flowers, vegetables, trees, and shrubs. blocks weed seeds from germinating in your garden for up to 3 months, and gives your plants a boost of plant food for beautiful, radiant blooms. is a natural way to keep weeds from sprouting in your vegetable garden. Providing 4-6 weeks of weed protection, Preen Natural can be used around any plant, including established vegetables, herbs, and fruits.
Remember, every weed flower you prevent or eliminate now could translate into hundreds of fewer weeds you’ll have to deal with later.