Phil: Hey guys it’s Phil from smilinggardener.com. It’s actually getting warm at here, I think this might be the last video where I am wearing my faithful green sweater here. If you haven’t picked up my free online organic gardening course, you can do that right on the home page of smilinggardener.com.
Today I am talking about organic weed control. Now for many of us organic weed control means we are down on our hands and knees for hours at a time pulling weeds, you can tell right now but I was down on my hands and knees and we really start to after a while to think that weeds are the enemies, especially weeds like bindweed and some of those grassy weeds which just keep putting up shoots all over the place. I am going to give you some tips on how to kill weeds naturally today but first I want to talk about the benefits of weeds some of us realized you know that can’t be just that simple that weeds are all bad, the truth is weeds are soil healers.
A number of weeds are nitrogen fixers like this is vetch and this is something I actually planted as a cover crop but it is helping to get more nitrogen into the soil, same with clover is a common weed, people would call the weed in the line even though it wasn’t long ago that it used to be included in lawn seed and it’s coming back a little bit today the people started to do a little bit of that but that is a nitrogen fixing plant. It’s working with bacteria to help improve the nitrogen in the soil, other than pulling weeds by hand there are number of things you can do. I am going to give you six of them today.
If you get cheap seed it’s going to have a lot of weed seeds in and you don’t want to do that, likewise when you are bringing in compost or when you are composting, you want to make sure you are creating a hot compost pile or buying really good compost for most of those weed seeds will have been killed because if you spread compost that has or top soil that has horse tiller or something like that you are bringing that into your garden. It’s not a great thing, so that’s number one as try to be clean. Second step is balancing your soil fertility and actually that’s what I was going to bring out my soil test for I remember now.
So I am not going to get in much detail here but when I look at this organic soil test result I can look especially at my main macronutrients here. I can see my calcium, magnesium, potassium, sodium those are all a [indiscernible 02:02] which is certainly common but if we can balance those out based on the recommendations from a good organic soil lab, we will start to see our weed pressure go down, a trusty hope.
Now it’s not always going to kill the weeds but if you just keep doing it a few times, it’s going to weaken them and eventually they wouldn’t cause that much problem, but dandelion, it’s nice if you can pull up that by the tap root it takes so long, now for me personally I leave most of the dandelions in my soil because I know they are doing a lot of good work there but if I did want to get rid of them and this is one handed I would just take a whole and boom, I didn’t get rid of everything but I got rid of a lot, you know the worms like to hang up right in the root zone of a weed. So, that’s another reason weeds are good. Next, how I am going to stop that dandelion from coming up again, well dandelions happen to be pretty strong, they keep come in back otherwise you can weaken them over the time but the next step to controlling weeds is boom.
Throw a nice thick mulch in there leaves or straw or whatever you like to use for mulch, I talked about that before but that is going to stop most weeds from coming up. Let’s go have a look at okay. Let’s check out this new garden that I put in last fall, not a whole lot of weeds going on in here either and that’s because of mulch, does so much to stop weeds. I had a leaf mulching here over the fall and just actually in the last couple of days having lend on a little straw because some of the leaves blew over to that side of the garden, so now I am laying down straw, those are my two favorite kinds of mulch and I do not have any weed problems in this garden.
The next step is to plan very densely, plant poly cultures which are groups of different kinds of plants that all work together to help each other out and the shadow of the soil, now I don’t have much going on this year. Here is my little strawberry batch. It doesn’t have much weed problems because it’s pretty dense on it’s own when it gets going and plant other things in there and I smoldered it with leaves so that’s not a great example this time year and there is the last step right there if you are in a pinch in it vinegar, just regular household vinegar, it’s 5% ascetic acid by volume.
It’s going to get rid of some of those you know dandelions and those really strong perennials but they do a really good job on animals and it will weaken perennials too just like aa hoe does over the time. So, what you do here is you put this in a spray bottle and just spray it especially nice for sidewalks and patios, but even a little bit in the garden is not too big of a deal, now if you want something a little stronger, you can buy horticultural vinegar, it’s 10% to 30% ascetic acid now it’s pretty caustic stuff very ascetic. It can burn you, you got to be careful with it but it can be used with you know to kill more perennial weeds, so those are your six steps. So how to kill weeds naturally, the big thing here is to take a long review.
So all of these other lessons I am teaching you had a balance of your soil and get organic matter in there, all of that stuff is going to create a soil that doesn’t support weeds very well, they just wouldn’t be able to thrive there. So that’s the main one along with smoldering them out with a nice thick organic mulch with very dense plantings or plants with a very dense healthy line, it’s especially important to balance your soil and have a good healthy line to compete weeds there because in the garden we can put a thick mulch on and that can cover a lot.
So that allow me really need to make healthy and that’s what we gotta do that. So the question today is what are your main problem weeds. If you can post that down below I will try to give you some tips specifically on how to deal with those weeds or I will try to tell you if there are any fertility issues that those weeds point to, other than that you can read more detail in this article down below, you can subscribe to my free online course down below that, you can join me on facebook.com/smilinggardener and I will see you next week.
Benefits Of Weeds
Many of these annoying plants we end up plucking from our garden beds are pioneer plants.
That means it’s their ecological job to restore imbalanced soil to a state of health.
This is why many weeds either host nitrogen-fixing bacteria – for example, clover, trefoil, and vetch – or accumulate particular mineral nutrients like thistles, dandelions, or plantain.
They share these nutrients and organic matter with the soil when they die, feeding the soil bacteria and nourishing the soil food web.
They also support healthy soil ecology by exuding nutrients through their roots while they’re alive, as their determined taproots break up compacted soil and improve tilth.
Weeds are generous givers!
What Weeds Tell You About Your Soil
Just as healthy plants don’t attract insect predators, well-balanced soils are much less likely to grow weeds.
We can even make some reasonable guesses about what’s going on with our soil, just by seeing which weeds are showing up.
For example, groups of grassy weeds tend to indicate low available calcium in the soil, while broadleaf weeds suggest a lack of phosphate relative to potash.
This doesn’t mean we should run off and apply single-nutrient organic fertilizers willy-nilly just based on the presence of a few dandelions, but weeds can add color to the picture of our overall soil health and can help confirm soil test results.
Still, in the meantime, I know you want to get rid of them, and the good news is there are many organic weed control methods other than pulling them by hand…
Organic Weed Control In 6 Steps
We can start first by doing what we can to avoid bringing them into the garden through low-quality seed mixes or improperly composted manure.
It may seem surprising that seeds could germinate even after going all the way through a horse’s digestive tract, but it’s true! The compost needs to get hot to kill these persistent little packets of life.
The second step is to balance the soil nutrients. Our plants want balanced soils, while weeds thrive on imbalanced soils.
I’ve been amazed to see insect predators leave plants and move over to the weeds as soil nutrients become more balanced.
Balancing the soil is especially important for organic weed control in lawns where we can’t use a mulch to smother out the weeds.
Which leads me to the third tip for how to kill weeds naturally – you’ll want to keep a nice thick layer of mulch on the soil all the time, once your seedlings have grown enough to reach light above the mulch.
Mulching is helpful for any number of reasons, not just for weed suppression, but this would be a good enough reason on its own. If you have a large home garden, mulching can save you dozens or even hundreds of hours over the course of a year.
The forth organic weed control tip is to crowd weeds out by planting densely, and planting polycultures of different plants that will keep the soil shaded.
There will pretty much always be something that grows on bare soil, so if you can keep the soil covered in multiple levels of desirable plants, the weeds won’t be as big of a deal.
The fifth organic weed killer, for those weeds that do make it through, is using a sharp hoe and cutting them off just below the soil surface.
It’s less work than hand-pulling and can be very effective, especially for annual weeds. Even for perennials, it will weaken them over time.
The sixth step is to apply boiling water (only good for small areas obviously) or spray them with household vinegar (5% – very safe but not so useful for perennials or other tough weeds) or horticultural vinegar (10-30% – can burn your skin pretty bad, but works better).
How To Kill Weeds Naturally
Take a longer view.
Soil is full of seeds and bits of root, waiting weeks, years, even decades for the right conditions to germinate.
When that moment arrives and the soil lies bare, these dormant seeds will spring into action like liability lawyers in a trauma ward.
So there’s really very little point trying to eliminate weed seeds and roots from our soil.
Instead, we can keep our soil healthy and well covered with plants and mulch, so weeds can take a nice long holiday from their job as healers of imbalanced soil.
Bindweed….or sometimes known as wild morning glory….I think I have it eliminated and it pops up some place else.
Apparently if you get that calcium up to where it should be, and also, phosphorus, you can keep it under control. Those 2 nutrients are likely deficient with most weeds. But I agree that bindweed does tend to find a way back.
Where do you find calcium for the garden..the bindweed is so bad I have heard the only way to get rid of it is to move! Okay phosphorous I can find.. but how much do I put down and should I wait until the growing season is over or wait till next spring.
Some fertilizer, farm or hydroponic suppliers will have it as calcitic lime or calcium carbonate.
I have heard that corn gluten is a good organic weed killer? But you have to find it at a garden shop.
It works okay on certain weeds if used correctly. It’s also a great nitrogen source. Unfortunately, it’s pretty much all from genetically modified corn.
i love this approach — great balanced advice — thanks phil for your real organic perspective!
Last year, our backyard was taken over by purslane. This year we have a lot of dandelions and crabgrass. I also see patches of clover and chickweed. It helps a lot to know some of them have medicinal properties. Now I no longer see my yard as being full of weeds. Instead, I think of it as my “herb garden.”
Purslane makes a great salad! just chop it up, mix with chopped cucumber & tomato, dress with lemon juice.
The dandelions and crabgrass often indicate a compacted soil without much organic matter. Also low calcium and phosphorus, which the purslane indicates, too. The chickweed may be an anomaly because it seems to thrive when there’s too much organic matter that isn’t being broken down fast enough.
Where do you get horticultural vinegar? I’ve heard of it, but have never found it available for purchase.
Here’s one example: https://www.groworganic.com/natures-wisdom-vinegar-20-1-gal.html
We get onion grass this time of year, and my husband has tried to dig the roots up over time (we live in the suburbs of Philadelphia). This year, they have come up with a vengeance, and we are not getting any younger. Any help to rid our grass of these weeds? Thank you!
You can eat them! Raw or cooked 🙂 Other than that, I would focus on improving grass density this year so the grass can largely outcompete the onion grass.
I live in a rural area of Idaho with lots of wild land and horse property around me. Most of our acreage is wild. I have what I have always called “Orchard Grass” as the main weed in my yard. I smother it out of my flower beds and garden because tilling makes it worse. But it is all through my lawn in great clumps and some of my lawn is just orchard grass (even though we have tried to seed over with grass seed.) Is there any organic way to get rid of it besides starting over with a new lawn? And how do I keep it out in the field and not sending its tenacious grass roots back into my yard and garden?
Only way I know of is starting a new lawn, but even then, will the orchard grass be gone? Probably not. It’s persistent stuff – farmers use it for hay. Unfortunately, I have no info on what it might say about your soil.
Hi Phil and thank you so much for theadvices you are giving out My weed problem is Creeping Charlie. What is the soil trying to tell me and how can i get rid of it without distroying the existing lawn? Thanks, AG
I have lots of experience with it. Tough to get rid of. You might search the internet for info on using boron, as there is research showing it can be effective. And boron is an important soil nutrient, but of course you don’t want too much or it’s toxic. Other than that, your weed usually thrives in heavy, wet soils. The good news is it’s highly medicinal, so maybe just start harvesting it for salads and be happy you have it.
We have more Mugwort than anyone could know what to do with here on Long Island. How do we get rid of it? or what can we use it for to make it an asset in our garden? What does having it say about our soil or land?
It’s used medicinally for a LOT of things in eastern medicine, and you can use it as a herb in salads, etc. I don’t have my weed books with me here (I’m visiting Amsterdam), so I’m not sure if they indicate certain soil issues.
What do you think of using glass to edge beds? I have been wanting to take photos and post another gardening trick that I use. I haven’t seen anyone else use it. I use glass to do my weeding at the edge and between my rows( if there is enough space) and if it’s not too close to the plants roots. I have some old storm door glass and large sheets of plexiglass. Just lay them on the spot you want to kill the grass in. Leave it there for a couple of sunny days and then move on to the next spot. The earth worms and other insect have a change to move on. Most grass will come back eventually because the deep roots are still there but that is good because it controls the erosion you may experience with digging and pulling. Does this make sense? If not, I’m open for questions. (I mostly do intensive gardening so the plant’s own shade does the mulching, but while I’m waiting on the okra to spread I can use the glass to keep down the weeds until it does.) Compost mulching is also great. Have you cked out Hugle Culture? We are starting some hugle beds soon. PS, I started using the glass when grass kept growing through the 4ft wide, industrial netting that I lay on the ground around the garden to keep the deer out. They view it as a cattle guard and won’t cross it, or at least so far. Thanks so much for all the wonderful info.
The glass works really well on new ground where you want to start a new bed.
Sounds like a good idea. It seems you’re using heat to kill the grass, and ya, animal life has time to get out of there. Cool!
I’ve read that boron is needed for brussle sprouts, but how do you get boron into the soil? I’ve not found any such products. I’m a bit skeptical about diluting Borax. Secondly, when using vinigar, won’t that alter the soil PH?
Borax is actually just fine for supplying boron, but I don’t recommend using it unless a soil test tells you you’re low in boron. Maybe you already have enough or too much. As for vinegar, it won’t have much affect on soil pH.
Do you happen to know what wild violets indicate?
No, I’m not sure about them.
Hi Phil, pretty new to gardening and really enjoying reading your articles. We always have lots of creeping buttercups in the back section of our lawn. I’ve read that those tend to favour highly fertile areas which could be down to our rabbits using that section as their toilet area when they had free run a few years ago – that area was very lush and green!! Other than covering the creeping buttercups with cardboard to stop them spreading, what would you suggest to get rid of them?
I don’t have any short term measures. It all comes back to improving soil nutritional balance, biological diversity, and humus.
Quack grass encroaching on and infiltrating my garden beds, shamrocks, and one that shoots seeds when you touch it in the beds. I have put cardboard and wood chips on the paths which works well but takes a lot of work. I have a lot of paths.
Where there’s bare ground, something will always come up. Quack grass is definitely a bit of a pain, but the cardboard and chips will help (for awhile).
Why does Canada Thistle love all the yards in my neighborhood?
Common reasons are low calcium, perhaps low magnesium, low manganese (often because of high iron), and poor soil biology that isn’t properly breaking down organic matter. You could add 10 pounds of calcium carbonate per 1000 square feet, and start using some microbial inoculants like effective microorganisms and mycorrhizal fungi (more info here: https://www.smilinggardener.com/sale/organic-fertilizers/ ) along with just a small amount of high-quality compost. A soil test would tell you more about magnesium, manganese and whatever other minerals are deficient.
Does using grass clippings contribute to more weeds coming up? Also, where do you get the straw that you use?
If the grass clippings contain weed seeds (like if they’re cut later on in the year from a lawn with weeds that have gone to seed), it could promote some weeds.I get my straw from an organic farmer nearby. It might be possible to get some from a farm supply store or more rarely, a garden center, or ask someone who has horses where they get theirs, etc.
Can I use vinegar to get rid of Poa annau?
Yes, I’ve seen that work.
Hello there Phil! I saw your youtube today and am excited to be learning with you. We are planning a homestead and I believe your wisdom will prove to be very helpful! In the meantime we have an issue with a rental home lawn. The last tenants DESTROYED the yard by storing things outside in the back yard. The yard is now full of weeds and we need to lay sod. We are in the Denver CO area (namely Aurora) so the soil conditions are poor. Sandy and clay. We are wanting to use the organic methods to support our own beliefs but also because the family has a 2 year old and Mom is expecting another baby. The weed and small spots of undesirable grasses are fairly well covering the area. We have thought of using vinegar or putting down black plastic to kill of the weeds. We are running low on time because the property is for sale and this beautiful little family would like to enjoy the outdoors too. Any ideas for killing off the weeds, preparing the soil and laying the sod? Will vinegar make the soil to acidic for the new grass to grow? Generally speaking people tend to use a blend of fescue and Kentucky bluegrass here. This is something we need to accomplish in the next 2-3 weeks to avoid the heat of the summer and perhaps dry weather. The soil has not been tested but it is very pale in color…sort of a khaki medium tan color. I am sure to be adding topsoil and compost but do you have any other ideas for offering a great growing environment for the grass?
Unfortunately, preparing soil for a lawn is far too complex of a topic for me to cover in a comment here. And having a lawn without weeds is a rather unnatural thing, so it makes sense that it would be a lot of work. But I will say that vinegar and plastic are fine to kill the weeds. If you just use household vinegar, you’ll only kill the young annual weeds, or you can buy stronger ‘horticultural vinegar’ that will work better, but don’t get it on your skin. Either way, the vinegar won’t cause problems for the soil.But after that, the issue is that the conditions that promoted the weeds in the first place are still there, mainly poor soil. To fix that requires knowledge, work and time. Briefly, you need to send a soil sample to a good organic soil lab and follow their fertilizer recommendations, plus probably incorporate some high quality compost (usually no benefit in bringing in topsoil), plus probably use some liquid organic fertilizers and microbial inoculants, and then water the new sod well to get it established, and keep it watered throughout the summers to keep it strong enough to outcompete the weeds. I know, it’s a lot of work to establish the kind of lawn most of us want, because it’s not really something you find in nature. Hope that helps a bit though.
Any tips for Japanese Knotweed?
No, nothing specific other than perhaps a calcium deficiency.
How do you get rid of dollar weed organically–both in the lawn and in the beds?
I have have big problems with oxalis and chickweed. I have tried laboriously weeding them but bulbs always remain somewhere so it only works for awhile. Can you you help.
Can you explain more about why you recommend seeding clover? We live in a newer development and clover is everywhere along the common areas and this year is all throughout our lawn. We don’t really care for the lawn to be all grass, but there’s double the clover this year and I don’t want it to be all clover either. We’ve considered cutting it out and patching with sod, but I don’t want to do that if we’re still going to have the problem. We’re in VA – very dense clay.
The reason I recommend seeding clover is because it does a lot to improve soil. If the clover is winning it’s because the soil conditions are better suited to it than the grass, so you’ll still have the same problem if you re-sod.
Although grass is not considered a weed, it is worse than a weed if it is where you don’t want it. Bermuda Grass is in my opinion worse than Johnson Grass because with the Johnson Grass, you can pull the runners out much easier than with the Bermuda Grass and stop the spreading quicker. I have been using vinegar and lemon juice which works well on most weeds, but on the grass it just seems to slow it a little. Any suggestions?Thanks, Ike Wiley
My main suggestion would be to learn to love the Bermuda grass. Not what you want to hear though, I know. You could try a ‘horticultural vinegar’ of 20+% acetic acid sprayed on a hot, dry day and then again a few days later.
I have a horsetail issue at my parents house. They have a 300′ by 6′ flower garden, so overwhelming for hand weeding. Any ideas? I am an organic gardener.
Horsetail can be tricky to get rid of. Can you move your garden? Haha, I know that’s drastic, but that stuff tends to stick around forever. The cool thing is that it’s actually a highly prized plant in the biodynamic world, good for making an organic fungicide, among other things – you could put some in the teas you’ve been making. It tends to favor wet and poorly draining, low fertility soils, so if you can boost fertility and not overwater, that will help. But the plant shouldn’t have a negative impact on your garden anyway. I wouldn’t go the herbicide route, and roundup doesn’t work well against horsetail anyway, but you could try horticultural vinegar to keep it under control.
I manage a community garden in southern Ca. and we are over run with white top, or hoary cress. I am a permaculture designer and am interested in dealing with the opurtunistic little guest by adressing the soil deficiency that it is there to solve.. Do you what might be lacking and where do I go to find this out for myself? My, couple of hours of study have not turned up anything for me.. Please help if you are able. Thanks!
Did you ever get an answer? I am wanting to do the same with our white top
I must have missed Shane’s question the first time around. Here’s a quote from the book Weeds: Control Without Poisons by Charles Walters: “Hoary cress can’t stand prosperity. A proper calcium level with other cations in balance, plus biologicals that return life to the soil, are the best bet for non-toxic control.”
He also says it should be handled like bindweed, which is “a typical reflector of an improper decay of organic matter and excess accumulation of heavy soil metals…”low calcium, phosphorus, potassium and pH are all benchmarks…with compaction, sedimentation, and improper tillage timing figuring in the equation…Correct these soil limitations through pH management and the bindweed-morning glory syndrome becomes completely dispersed. No herbicide chemical or fertilizer material can replace good soil management. Roots that go down 4 feet in the first year can’t be chased by phenoxy herbicides.”
So much wisdom in this classic book!
I hope you can help me identify a very invasive weed. It looks like strawberries . I have to make sure I am wearing thick garden gloves when i pull it because if it touches my skin it tingles, burns and causes numbness to travel from my hand to forearm. It propagates by stolons. Thanks
Duchesnea indica (Mock strawberry)?
I have been told that I can use potash on the asparagus patch. That it will keep quack grass under control.
what are your thoughts on this?
I’d be surprised if potassium would help control quack grass. I tend to think of potassium as, if anything, more of a promoter of weeds than a controller of them because it often contributes towards the compacting of the soil.
Great post, the fourth tip is interesting. I’ll try to plant polycultures of different plants to keep the soil shaded. I guess that’s a good idea.
Keep it up,
How do I get rid of Khaki Weed ? Any organic suggestions ?
Unfortunately not – that’s a foreign weed to me. I’ve heard if you can dig it out for a few years and get rid of the seeds, you can control it.
We built a home in WA 30 years ago and are unfamiliar with the weeds here. Once we were able to enjoy our gardens we were surprised when a weed that looks like very skinny asparagus. here it is know as “horse tail”. We have tried just about everything but have had no success in ridding our gardens of this noxious weed. Do you have any suggestions. A neighbor suggested using lime. Have you heard of that?
Horsetail is nearly impossible to get rid of. The cool thing is that it’s actually a highly prized plant in the biodynamic world, good for making an organic fungicide, among other things – you could put some in the teas you’ve been making. It tends to favor wet and poorly draining, low fertility soils, so if you can boost fertility and not overwater, that will help. But the plant shouldn’t have a negative impact on your garden anyway.
Spray Horsetail when the weather is HOT. The pores will be wide open and then as it cools down in the evening will be absorbed down to the roots.
Hi Phil, Thanks for sharing all your gardening wisdom throughout the years. Love your posts and books!
I know this is an old thread, but wanted to let you know how we remediated Horsetail. We took over a neglected yard/garden in mid Vancouver Island where horsetail thrives. Many gardeners were using Roundup! Yuck! Hard to educate some folks…Luckily, we met Scott from Healthy Soils who taught us about Soil Microbiology and ‘building’ soil ecology vs a ‘killing & poisoning’ mentality. So we focused on healing the neglected or abused soil terrain.
With an in-depth soil analysis and his recommendations, we added fish compost, rock phosphate, worm castings, lime, kelp and other ammendments including spraying EM and compost tea. Within 2 years the Horsetail just ‘disappeared’ and the perennials and vegie gardens thrived! Now we’re in Victoria and have Bindweed. We would trade Horsetail over Bindweed any day! Anyway, we’re so fortunate to have your advice along with the Gardener’s Pantry here for education & supplies!
Keep Gardening & Smiling!
I have asian jasmine ground cover that has clover and dollar weed growing in the ground cover. What are the options to killing these two weeds. You can pull the clover and it is back in 2 days. The dollar weed is impossible to pull with those tiny roots that run under the soil.
Yes, this is one of the most challenging weed situations to deal with because whatever you do to the clover and dollar weed will be done to the Asian jasmine. Alas, I don’t have any good answers.