TestDIYOrganic

Linda asks:



I think I need to add something to the lawn to help dethatch naturally.and maybe help the soil.  Would spreading a commercial packaged manure mixture be helpful?  At 98 cents a bag I could cover the lawn with 30 bags.



Also would you suggest an application of ammonia sulfate in the Fall to help balance the ph from years of chemicals?



thanks! ;-)




There are a few different questions here and I'll answer them one at a time. This is general advice when converting to organic lawn care.

Naturally Dethatching

First, thatch isn't a bad thing to have in your lawn. It's when you have more than a 1/2" of thatch that it can be a problem. Take a spade or shovel and cut out a square of your lawn to inspect the profile and measure the thatch layer. If it's more than 1/2" then you'll want to do something about it.



The problem with thatch is that it can prevent air, water and nutrients from going down into the roots. There are two ways to resolve this problem. One is to mechanically dethatch, the other is to core aerate. I discussed aerating vs dethatching previously. Basically dethatching removes the thatch layer and aerating creates holes in the lawn that allow air, water, etc to penetrate into the root zone.



Soil microbes and other organisms in your soil such as earthworms will help break down the thatch but lawns that have had years of synthetic fertilizers and pesticides applied will have poor soil biology and likely soil compaction. Adding compost to the lawn will improve the soil biology as well as add organic matter in the soil.

Adding Compost

Compost does a lot of great things to the lawn. It improves the soil structure, adds organic matter, helps relieve compaction, adds nutrients and enhances soil biology. It is the best thing you can add to your soil when converting from synthetics to organics. Some microbes found in soil and compost help break down the chemicals in the lawn from synthetic fertilizers and pesticides.



The EPA has published this information sheet on compost describing it's use for bioremediation, disease control and other issues. Compost was even effective in remediating soil that had explosives in it!



From what I've learned it's best to use a mix of compost from different sources. Compost from plant material and composted manure. I would personally go heavier with the plant based compost because if the composted manure is not composted completely it can cause problems.



30 bags of compost at I'm assuming 2 cubic feet per bag is 60 cu ft is over 2 yards. I think you'll be better off having that compost delivered in bulk. Find a local source of plant based compost that will deliver. Lay a tarp on your driveway for them to deposit it on so it doesn't create a mess. I haven't used one but I've been thinking a Bagster Dumpster in a Bag might be good to use. Buy a few bags of composted manure and mix it in. A pitch fork works well but you can do it with a shovel too.



If you don't have a wheelbarrow, borrow, rent or buy one to help you distribute the compost and use a rake to spread it in. The Ames True Temper Kodiak Forged Level Head Rake is a good rake for this purpose.



To figure out how much compost you'll need determine the square feet of your lawn area and how many inches of compost you'd like to apply. Use the following formula.



(square ft of lawn) X (inches of compost) / 12 / 27 = Yards of compost.



If you had 5000 sq ft of lawn area and you wanted to apply 1/2" of compost it would be:



5000 X .5 / 12 / 27 = 7.7 cubic yards of compost.



It's roughly 3/4 of a yard of compost per 1000 sq ft for every 1/4" of compost you want to apply.



To determine the square footage of your lawn you can use the property survey that's likely attached to your mortgage (or you can get it from your local tax assessor I think) and use that as a guide. You can even try downloading Google Earth and using the satellite images and measuring tools to measure your lawn but going out and taking direct measurements would be the best.

Soil PH

I wouldn't add anything to the soil to adjust the pH unless I knew what the pH was. Don't guess. Send a sample of your soil to get tested by your local university cooperative extension for analysis and use that information to adjust the pH of your soil. Most likely you'll need to add lime.



The soil report you receive will give you recommendations on nutrients in your soil but will most likely recommend synthetic fertilizer applications. You can use organics instead but will need to calculate how much fertilizer to apply. For example if they tell you your soil needs 1.5 lbs of potassium per 1,000 sq ft then you need to figure out how much of your organic fertilizer to apply to give you 1.5 lbs per 1k sq ft.

What I Would Do If I Were You

Right now is the best time to start the process.



1. Determine your soil pH either by sending a soil sample to your extension office or by using a consumer soil pH tester like the Luster Leaf Rapitest Mini Soil pH/Moisture Tester. If you use the soil tester it's important that the soil is moist to get an accurate reading and you should test different locations and take an average.



2. If you have more than 1/2" of thatch I would dethatch the lawn. I don't have a large lawn so I use a manual dethatcher that also helps remove ground ivy and gives a good workout. :) If you have a larger area rent a gas powered dethatcher.



3. Whether you dethatch or not I would core aerate the lawn. Again, I have a small lawn and like to sweat so I use a Turf Hound manual aerator. Based on how much compost you're thinking of getting I assume you'd want to rent a core aerator. Many rental places will carry them. Make sure it's a core aerator and not a spike aerator. You'll want to run the aerator over your lawn multiple times in different directions. How many times you go over your lawn will depend on your model. You want to get at least 9 holes per sq ft but as many as 20 holes per square foot if your soil is very compacted or heavy clay. I'd shoot for at least 16. Leave the plugs on your lawn, don't rake them up.



4. Apply lime and organic fertilizer as needed. I've had good results with Espoma Bio-Tone Organic Starter Fertilizer. It has a good ratio of nutrients and contains beneficial microbes. Do not use corn gluten meal at this point if you plan on overseeding which I would.



5. Spread compost on your lawn. Get bulk compost delivered. If you can get a mix of composted plant material and composted manure that's your best bet. If not get the composted plant material and mix in some composted manure. Plain composted plant material is fine too. Because of the core aerating I would shoot for 1/2" of compost.



6. Spread a good quality grass seed over the lawn and water it as recommended to get good germination.



Starting next Spring use organic lawn fertilizers 3-4 times a year. Corn gluten meal in the early spring and late summer, Ringer Lawn Restore in late spring and mid fall would be a good star. Also using a pump sprayer (I like the Smith 2-Gallon Max Contractor Sprayer)  to apply soluable kelp and humic acid in late spring and a one or two times during the summer would be great. You can mix the kelp and humic acid and apply them at the same time.



Also read my mowing tips for a healthier lawn.



Hope this helps!

A quick update on the two grasses I'm growing indoors in containers. One's doing well, ran into a problem with bugs in the other used neem oil to kill them. Happened to catch it all on video which is included further down.



The picture on the left is the Jonathan Green Black Beauty at Day 6. It has germinated very well and some shoots are still popping up. Average blade length seems to be about an inch with some about 1/4" and half a dozen or so that have grown about 2" long.



Black Beauty displays significantly more phototropism compared to the Jonathan Green Dense Shade I have growing next to it. During the day the Black Beauty blades are pointing towards the window. After the sun starts to go down I turn on the room light so it can get a little more light and the blades start to stand upright fairly quickly. I'll be able to demonstrate this a little better in a few days.



So far it's looking pretty healthy. Germination was a lot better and more even than the Dense Shade and that's most likely due to the age of the Dense Shade. It was an old bag that was 3 years old. I should have taken the time to buy a new bag.



These are pretty ideal conditions for the lawn other than sunlight. Temperature controlled environment, good pH, growing medium rich in organic material, ability to keep the seeds moist throughout the day.  The grass is getting some indirect sun from a couple of North facing windows and I supplement that with some artificial light from time to time.



From the top it doesn't look as impressive yet but you can see how even the germination was.






In a week or so I think it will fill in much better. From the side it's already looking pretty good.



The Dense Shade on the other hand hasn't been fairing so well on Day 22. On Day 17 it was looking decent except for some areas with poor germination which as I mentioned was likely due to the age of the seed. I had topdressed with some additional organic potting mix, added more seed and another small layer of potting mix. I also switched to filtered water at that time.



As you can see it's filling in a bit but the grass has gone a bit limp and lost some of it's color.








The growth seems to have stunted although some of the new seed is germinating and filling in the bare areas. Some of the older grass tips have browned. It looks like insect damage and I did see a couple of small critters on the grass which I squished. Not sure what they are or how they would have come inside. They were tiny flying bugs. I haven't seen any on the Black Beauty which claims to be naturally resistant to some insects.



Uhm... since I wrote that last paragraph I found out it's definitely bugs! I'm doing a time lapse recording of the growth and what I thought was some sort of video artifact is actually little tiny things crawling around. I sprayed some Organica K+Neem on them which seemed to work pretty well. K+Neem is no longer made but other products like Green Light Organic Neem Concentrate are still available.  Neem oil is a contact killer and doesn't have any residual effects. In a couple of days if I still see any I'll spray again.



Here's a portion of the video. You can clearly see the white bugs (larvae?) crawling around on the potting mix on the bottom right. In the middle of the video I sprayed the neem oil which put an end to them. The bugs are really tiny so you might need to watch the video in HD and fullscreen to notice them.





Black Beauty is supposed to be naturally insect resistant. I'm not sure if that's why nothing is crawling on that side or not?



After some research and having a closer look at one of the adult ones, it seems they were fungus gnats. Some more Googling and it seems other people have complained about gnats in Jungle Growth Organic potting mix. Don't know if they came in the mix, found they're way through a slightly damaged screen came in the door or hitched a ride on a pet. I'm going to keep a close eye on it. Have noticed a couple of gnats since I posted this but don't see the gnat larvae crawling around on the soil like before.



I'm hoping that the Dense Shade perks back up soon. The topdressing might have stressed it, the bugs surely did and while the neem oil shouldn't harm the grass too much could cause it problems.



Here's a top view.






It doesn't look as good compared to the Black Beauty on the bottom but when the Dense Shade was young it looked much better too. We'll see what happens in the next few days.

Is Using Cornmeal to Treat Lawn Disease a Myth?

Not only does Dr. Linda Chalker-Scott consider the use of cornmeal as a fungicide a myth, an article from 2010 claims the myth is busted. Dr. Linda Chalker-Scott is the author of The Informed Gardener and numerous articles on horticultural myths



When I discovered Dr. Chalker-Scott's myth articles online a few years ago I read threw them all and found myself mostly agreeing with a lot of the content and was able to find corroborating work in other studies from what I remember. I even referenced her when I was asking myself... does SuperThrive work?



In this case however I find I can't agree with everything she says. Sadly, from the time I first started writing this piece, some of the links I originally quoted are now broken but I've tried to find similar research. The original article wasn't meant to be a rebuttal to Dr. Chalker-Scott but I tried to incorporate her opinions in the new version.



Note I actually started writing this article one or two springs ago which is why I have reference to all the rain. Right now it's the middle of summer and there hasn't been much if any rain but I'm leaving that verbage intact to illustrate what I was seeing at the time. I decided to finish it after seeing Dr. Chalker-Scott's article recently.



Well, it's been raining here for quite some time and it's going to continue for another week it seems. I've touched on the issue of lawn disease recently and it should come as no surprise considering the wet weather.



In the few breaks in the rain, I've managed to get in a few bike rides and there are plenty of brown, yellow or orange tinged lawns throughout the neighborhood. Brown and yellow could just be a result of lawn crews waiting too long to cut the grass as they try and squeeze what they can in between downpours but most likely a good bit of it is due to fungus caused by all the moisture and landscapers that are mowing the grass when it's wet because they can't afford to wait for dry weather.



As I look over my lawn and compare it to the neighbors there is a vast difference in color. Mine is a nice dark green, theres is a mixture of light green and orange (grorange?) Part of the reason for that is a much discussed organic fertilizer that tends to make people laugh or look at me funny when they hear what it is.



In the early morning when other's are mixing up cornmeal for muffins, I'm out spreading it on my lawn. Plain old corn meal that you can get from the supermarket. (Not corn gluten meal.) I've posted about corn meal recently (where to buy big bags of corn meal, how to get organic corn meal delivered every month or two) but with so many grorange lawns out there I thought it might be good to explain it a little more about how it works and how to use it as well as some other organic fungicides.

How Corn Meal Cures and Prevents Lawn Disease

Well the truth is, corn meal doesn't kill fungus. In fact, it does the opposite. I can hear you now saying "But you said...." Hear me out.




With organic lawn care, you're not usually solving the problem in one step. Instead you create a condition where beneficial organisms can thrive and/or add beneficial organisms. Such is the case with cornmeal.



The beneficial organism in this case is trichoderma, a family of cannibalistic fungi that kill other fungi. When you apply cornmeal to your lawn you're not killing lawn disease, you're supplying the troops of trichoderma so they can multiply and wage war on lawn disease.



The video isn't in a language I speak but I'm pretty sure based on the title and the footage that this is a video of trichoderma killing sclerotinia. A form of sclerotinia occurs in lawn and is commonly referred to as Dollar Spot.







Trichoderma are found in most soils and grow well on corn meal. Corn meal, like everything else that hasn't been sterilized, also harbors bacteria and fungi and trichoderma is a common fungi to find on cornmeal (I think from what I read). Even if it's not on the cornmeal it's a fungus that's commonly found in soil.



Three of the species of trichoderma that are used to fight plant and lawn disease are trichoderma harzianum, tricoderma viride and trichoderma hamatum. They are parasitic and feed off other fungi in a variety of ways. Trichoderma harzianum for instance can excrete and enzyme called chitinase under the right conditions. Chitinase breaks down, hydrolizes, digests, whatever you want to call it, chitin which is what the cell walls of fungi are made of. It basically disolves other fungi.





There are (were?) ongoing university studies that have shown promise using corn meal to treat plant diseases such as this study on controlling fungi in peanut fields with corn meal (link no longer works but is available on archive.org referenced here). My emphasis added.

It is known that certain fungal species in the genus Trichoderma feed on
mycelium and sclerotia of Sclerotinia minor. Sclerotium rolfsii and Rhizoctonia
sp. All peanut fields in Texas tested to date have a natural population of
Trichoderma. For several years, tests have been conducted in Texas using corn
meal to stimulate Trichoderma development as a way to control the major
soilborne disease fungi. When yellow corn meal is applied to fields in the
presence of moist surface soil, Trichoderma builds up very rapidly over a 5 to
10 day period. The resulting high Trichoderma population can destroy vast
amounts of Sclerotinia, Sclerotium and Rhizoctonia. This enhanced, natural
biological control process is almost identical to the processes that occur when
crop rotation is practiced. The level of control with corn meal is influenced
by: 1) organic matter source 2) soil moisture, 3) temperature, and 4) pesticides
used. Seasonal applications of certain fungicides may inhibit Trichoderma.
Testing will continue to determine the rates and application methods that will
give consistent, economical control.

The above quote is the reason why some of us started using cornmeal on our lawns in the first place. Dr. Chalker-Scott calls it "research" (with quotes) indicating it wasn't really following the scientific method. It's hard to say without being able to see the original report but from what I remember it seemed to have been conducted using sound principles. From what I recall, they didn't just guess that trichoderma populations increased, they actually examined the soil.



Dr. Chalker-Scott also claims the study just proved that crop rotation is a beneficial practice that can prevent disease. That's not what I'm reading here.



I'm not much of a conspiracy theorist but I do find it odd that the original paper and some of the others I linked to below are no longer online.



The study that led to the discovery of corn gluten meal as a weed control also had an interesting observation regarding corn meal and lawn disease. The original study was regarding pythium on bentgrass. Pythium was cultured in the lab on corn meal, which is a common growth media for such fungus. There were three plots observed. A plot which received the pythium and corn meal, a plot which received fresh corn meal without pythium grown on it and a third control plot which did not receive any pythium or corn meal. Pythium failed to establish in the treated plot where the pythium grown on corn meal was applied. It seems Dr. Nick Christians Ph.D. focused more on the lack of germination in the corn meal plot as I can't find any documentation that he tried to determine why the pythium may not have established.



The previous quote from Texas A&M doesn't say anything about lawns or common lawn diseases does it? Hmm... OK this is the problem with organic research. While it has been studied for a long time, it unfortunately hasn't been that long and you may not find direct evidence of exactly what you're looking for. So this is what we do, or I do at least. I'm not the type of person that likes to waste money and see if something works just because someone said it does. I want to see something that justifies the claim. Sometimes you can't get to it directly so you have to find corresponding research and peice it together without getting so convoluted that it looks like a Chewbacca defense.



Now that we know it's not actually cornmeal that's curing the lawn disease all we have to do is look for research that indicates trichoderma is effective at killing a particular diesease. That shouldn't be too hard because according to the Wikipedia article there's a strain of trichoderma that can kill almost any other fungus and trichoderma is found in all soil. Maybe not in soil that has been treated with some fungicides such as chlorothalonil (Daconil) but some species of trichoderma seem to be resistant to copper based fungicides.

Lawn Diseases That Corn Meal Can Treat

Well theoretically treat that is. I'll be updating this list as I have time but here's a quote from a Cornell publication on trichoderma:

So far as the author is aware, different strains of Trichoderma control every pathogenic fungus for which control has been sought. However, most Trichoderma strains are more efficient for control of some pathogens than others, and may be largely ineffective against some fungi. The recent discovery in several labs that some strains induce plants to "turn on" their native defense mechanisms offers the likelihood that these strains also will control pathogens other than fungi.

These are common lawn diseases that trichoderma attacks. If you can get trichoderma to grow on your applied cornmeal then there's a chance for corn meal to treat the following:



Sclertinia (Dollar Spot) - See video above and this paper found trichoderma provided up to 71% control of dollar spot and was able to delay disease development by up to 30 days.

Botrytis (Grey mold) - An interesting study at Cornell (link dead) using bees to disseminate Trichoderma harzianum to protect strawberries from Botrytis was effective. Here's a working link that discusses using trichoderma to suppress Botrytis of Begonia in a peat/compost potting mix.

Pythium - A nasty lawn disease can be controlled with trichoderma harzianum and trichoderma virens according to this PSU paper. There are even two products that contain trichoderma that are EPA registered for treating pythium. The link to the paper is gone but this PSU fact sheet indicates Trichoderma harziamum, Trichoderma virens as well as Bacillus subtilis, Candida oleophila, Gliocladium catenulatum and Streptomyces griseoviridis are biological controls of pythium.

Fusarium - There are a number of documents indicating trichoderma is effective against fusarium including this Colorado State study on trichoderma against fusarium on tomatoes.

Necrotic Ring Spot - This publication indicates trichoderma hazrianum is effective against necrotic ring spot in laws and that there is an EPA registered product.

Drechslera tritici-repentis (Leaf Spot) - In vitro study showed Trichoderma "inhibited significantly the mycelial growth ofD. tritici-repentis between 50% and 74%"

Rhizoctonia solani (Yellow Patch) - This in-vitro study showed that various strains of trichoderma were up to 81.8% effective at inhibiting mycelial growth of Rhizoctonia solani.

Organic Products With Trichoderma

In researching the topic I found a number of different products that contained trichoderma that were EPA registered fungicides.  The first time I used cornmeal on my lawn I did it without adding anything else and I found the application of cornmeal was beneficial to my lawn. It may have been the tricoderma, it may have just been that my grass needed fertilizer and the extra boost it got from the cornmeal allowed the grass to grow out of the disease or make it healthier so it could resist it. I'm not a horticultural specialist and I don't have the tools to know the difference.



These days, when I apply cornmeal to my lawn I also apply Organica Plant Growth Activator Plus using a pump sprayer that I filled up 2 days prior to allow the chlorine to outgas. Chlorinated water can kill the beneficial fungi I'm trying to spread. Humic acid and ascorbic acid (Vitamin C) are also said to reduce chlorine in water.



Organica's Plant Growth Activator Plus contains a number of beneficial bacteria and fungus some of which have been shown to prevent or control plant and lawn disease. It contains:

• Trichoderma hazianum 2,000,000 CFU per gram. 


• Bacillus subtilis 10,000,000 CFU per gram. 


• Bacillus licheniformis 10,000,000 CFU per gram, 


• Bacillus megaterium 10,000,000 CFU per gram, 


• Paenibacillus polymyxa 10,000,000 CFU per gram, 


• Streptomyces lydicus 2,000,000 CFU per gram, 


• 30% natural sugars, 


• 10% hydrolyzed soy meal 


• 4% humic acid (derived from leonardite), 


• 3% seaweed extract (derived from Ecklonia maxima). 

I can't find a link to the original Rutgers study but it's referenced here. Application of PGA+ every 2 weeks was able to control around 90% Summer Patch (Magnaporthe pose) on Baron Kentucky Bluegrass which is similar to the control rates of the other commercial chemical based fungicides. Even after application stopped the PGA+ test plot continued to provide effective control.



Organica's PGA+ is a product I looked into quite a bit and is something I apply in my garden regularly. The kelp and humic acid seem to work well together to reduce plan stress from what I've read.

Compost Helps with Plant Disease

So Does Cornmeal Cure Lawn Disease?

One comment Dr. Linda Chalker-Scott made which I do agree with is that there hasn't been enough scientific research to definitively prove if it does or not. She also stated that she can't prove a negative (that it doesn't work) and that it's up to those that are making the claims that it does work to prove it does.



I thought that's what the original Texas A&M group was doing and can't figure out why that link no longer works.



Here's what I do know:

• Various strains of trichoderma (as well as other fungi) are grown on corn or corn agar when researches need to cultivate a given quantity of the fungi. It is a good growth medium for such.


• Various strains of trichoderma have been shown in different studies to have effective control of various plant pathogens including ones that are found in lawns.


• Trichoderma are found in nearly all soils.

Here's what I assume:

• Since corn meal is a good base to grow fungi adding cornmeal to moist soil should be able to increase the population of those fungi.


• Since trichoderma is some sort of predator fungi that kills other fungi it's understandable that the population of trichoderma would outcompete the other fungi growing on the cornmeal medium since it will attack those other fungi. 

I think there's enough evidence related to using cornmeal and trichoderma to control lawn and plant disease that further research is warranted.

So what's the problem? Where's the research?

OK, it's time to put my tin-foil hat back on. Research isn't cheap. It takes time, resources and money. University research labs need to have funding to carry out their experiments. Who pays for that research? Some of it comes from government grants but I believe most of it comes from companies that are developing and patenting products for eventual sale. They work with university researches to determine if their new product works or not and try to improve it. They are willing to pay to have that research done.



Who is going to pay to research cornmeal? It's not patentable. It can't be sold as a commercial product.



You also need to be EPA registered if you claim your product is a fungicide. That's not free either.



More research needs to be done as fungicides are some of the more toxic things applied on lawns, but just because she can't verify the claims doesn't mean Dr. Chalker-Scott can call this myth busted.

So Does Cornmeal Cure Lawn Disease?

I always wanted a little planter of grass on my desk so I decided to try a little indoor grass growing experiment to see how well it turns out.



I'm hoping it can survive year after year with proper care. Instead of growing it in soil I'm using an organic potting mix and I'm using a grass seed I've had good results with in shade. I'm hoping it does equally well indoors.



If you'd like to follow along with the progress of my indoor lawn I'll be posting it in the into the Grass Indoors section of my site.

Step 1: Prepare Planter

If any of you happen to know where I can find a planter that looks like the one on the right but smaller please let me know!





I filled the planter up to about 1" from the top with Jungle Growth Organic potting mix. There are many beneficial fungi in soil that help grass grow. I hope using a potting mix isn't going to cause any problems. I didn't really want to bring any dirt and bugs inside.

Step 2: Add Seed

I'm using Jonathan Green Dense Shade Grass Seed Mix. It's a seed mix I use in a shady part of my lawn and have had great success with it. The bag I had was a few years so I added more than the recommended rate in case some of it has gone bad. I know at least some of it is good because I had to seed a patch of lawn earlier this year and the grass came up.



The label on the bag lists the following cultivars:

• 29.45% Carmen Chewings Fescue


• 24.55% Hood Chewings Fescue


• 14.75% Eugene Creeping Red Fescue


• 9.83% Frontier Perennial Ryegrass


• 9.82% Darkstar II Perennial Rygrass


• 9.82% DeepBlue Kentucky Bluegrass


• 1.71% Inert Matter


• 0.04% Other Crop Seed


• 0.03% Weed Seed

Step 3: Mix the Seed

I used my hand to just gently work some of the seed into the soil and evenly distribute it along the top layer.

Step 4: Cover With Coffee Filters

I placed a layer of regular white coffee filters over the seed and soil to act as a sort of seeding mulch. It will help keep the seeds moist and provide a better indication of when the seeds might need more water.

Step 5: Water Grass Seeds

The final step was to water the seeds. I only added about a cup of water. I'll be adding more water 2-3 times a day using a spray bottle to keep the seeds moist.




The age of the seed gives me some concern but I'm hoping it works out. Add my RSS feed to your reader to keep up with the progress.

Glyphosate based herbicides like Roundup are commonly used to kill all grass and weeds when doing a full lawn renovation or to kill unwanted weeds and plants in garden beds. Glyphosate has generally been considered safe. When it comes in contact with soil it becomes inert but there have been concerns over it's use including this most recent one. It's definitely not a product that is allowed in use for organic gardening or organic lawn care.



If you are opposed to using Roundup in your lawn or garden there are some alternatives to Roundup that are approved for use in organic farming. If used correctly they can kill your lawn and weeds in preparation for reseeding.

Vinegar

Acetic acid is the main component of vinegar and can be used to kill grass and weeds. I've successfully been using plain old distilled white vinegar to kill weeds in beds and driveway cracks for years.




Horticultural vinegar has a 20% concentration of acetic acid, compared to about 5% for grocery store vinegar. It is more effective especially over a larger area such as a lawn. 20% vinegar is also approved for organic farming.



It's best to apply on the foliage of unwanted plants during a warm, sunny day. The way acetic acid works is it breaks down the cell membranes causing desiccation of the the plants. The heat and sunlight increase the rate of desiccation. The plants will typically die in a few hours.



The acid in the horticultural vinegar will not greatly affect the pH of your soil but follow appropriate guidelines when applying as acetic acid in this high a concentration can burn skin and cause severe eye injury.

Burn Out II

BurnOut II Weed & Grass Killer is a commercially available product made of a high concentration of citric acid and clove oil.



It is an OMRI approved organic weed killer. BurnOut II kills grass and broadleaf weeds. Just like horticultural vinegar it is best to apply it on a warm, sunny day to get the quickest results and follow the manufacturer's safety recommendations.

Nature's Avenger

Nature's Avenger Weed and Grass Killer is another commercially available non-selective herbicide that is OMRI certified and approved For Organic Gardening use.



It is another citric acid based solution that when applied to plants causes them to dehydrate and die. To improve the performance of the product it should be applied on a warm, sunny day.

Not As Complete As Roundup