SHOP BY DEPARTMENT
Houzz Logo Print
jennyinmn

Smothering lawn to use native plant seeds

jennyinmn
12 years ago

I have a 30x30 section of our lawn that is covered in clover and dandelions. I would like to convert it to an area with native grasses and flowers using a seed mix. We've researched the options for killing the current residents and are having trouble coming up with the best option.

Not too interested in herbicide, but if it were the last choice, I would consider one or two applications to help convert the area to native plants.

Tilling would be tough because there are 3 trees with fairly shallow roots.

Smothering seems to be the way to go, but if I use newspapers and mulch - the seeds won't be able to get to the soil to grow, right? It seems like newspapers and mulch are a great option if you're going to use plants, but not for seeds.

Or we could smother the lawn with black plastic, but then I'll have the huge amount of dormant seeds competing with my native seeds, right?

Thank you so much for your help.

Jenny in Minnesota

Comments (19)

  • anney
    12 years ago
    last modified: 7 years ago

    Jenny

    You could solarize the soil, but it requires coverage during the hottest part of summer, so you probably wouldn't be able to sow any seeds until next year.

    While I don't know if it would work, I've thought of solarizing parts of my garden each year and setting plants out in containers on top of the plastic so the growing space isn't entirely wasted for a season.

  • annpat
    12 years ago
    last modified: 7 years ago

    Do you have other hard to control, ugly weeds in the yard? I ask because your dandelions and clover are pretty wildflowers, and clover will almost certainly be a component of your wildflower seed mix, I bet. I have an unmown yard and the dandelions and especially the clover (mine is a tallish, huge-flowered purple and pink and cream variety), and one type of buttercup are really pretty in the spring.

    My soil is terrible after my virgin soil got robbed during construction ten years ago, the deep dark soil dug out and replaced with gravel/soil. A lot of ugly stuff came in with that replacement dirt. A blackberry, something with burs, and the worst of all, a pernicious (I've wanted to use that word this morning somewhere. (It doesn't quite mean what I thought it did, but what the hey.)) buttercup.
    This little, evil, nondescript-flowered, buttercup is taking over, so I'm trying to smother it area x area. I covered a huge area last fall with a 3' layer of compacted leaves. I was astonished to see the first green of the spring this year: those buttercups poking their heads out of that deep mulch. I am kicking myself that I didn't put a newspaper layer down first. They're slightly weakened, so I'm going to cover them with newspaper, seaweed and hay as soon as I can get to the beach, and hope that I can finish them off and quickly get to another area they're taking over.

    In other areas of my yard where the evil buttercup hasn't arrived yet, I am growing or buying or digging up wildflowers that are more attractive than my weeds and plugging them into those areas.

    My neighbors are really rude about my yard (I live on a dirt camp lake road, where originally no one mowed, so no one can really get annoyed with me.), and when they are in my yard, they think nothing of stepping off my indian paths and flattening a clover or a particularly handsome buttercup. When my neighbor Phil stepped on a nice, fat purple clover one day, offpath, I said, "You're stepping on a flower," he said, "What? This mess?" I took him by the arm and made him stand still and I pointed to the clover, the buttercups and the daisies in bloom under his feet and said, "You cannot tell me that that is not pretty." Then I took him to a less robust part of the yard and showed him my beautiful patch of fine grasses and yellow, red, and orange indian paintbrushes.

    "Ta-Dum!!" I said triumphantly.

    He still couldn't see it.

    Anyway....I would try to overwhelm your own wildflowers---your dandelions, your clover---with plugs you put in among them or I would smother the area with newspaper and a nourishing mulch this year and plant the wildflowers next year. As an organic gardener, the herbicide route is not an option for me. I've made a commitment to organic gardening that I keep even when the going gets tough. It'd be nice if I weren't an organic gardener, though, because dealing with my little buttercup is a difficult battle I may lose.

    Good luck.

  • Related Discussions

    Smother poison ivy and grow lawn

    Q

    Comments (4)
    there are exceptions to all rules. PI dies with minimal amounts of roundup. the secret is in applying RU with a small paintbrush on the leaves, undiluted, so that no other plant is affected. one or two leaves, touched with the brush, and the plant dies. As Kim says, there are giant roots under there, and PI will not get smothered. Look around for the larger vines climbing trees, they are particularly visible in Fall, when they are red against a bare trunk, and cut them at the base to eliminate the seed supply. They will produce a million small plants from the roots, and those you can paint next year to completely eliminate it.
    ...See More

    My Bermuda lawn is smothered by this weed

    Q

    Comments (7)
    Thank you so much rdaystrom .... looking at the link and reading about it some more, I'm almost certain my lawn is infested with Dichondra and/or maybe combination of both Dichondra and Dollarweed. Like you said, 2-4-D is what I should get and apply (although suggestion to apply is 'Late Spring" and we have Winter here in Georgia, I still may try some application to see the reaction) . Thank you very much for the info and the link! For others who might be curious about Dichondra, here's a link that has some more info http://www.turffiles.ncsu.edu/weeds/Dichondra.aspx
    ...See More

    Monsoon planting article from Native Seeds/Search

    Q

    Comments (3)
    I very recently identified amaranth and purslane as two greens I want to add to my garden. My Asian neighbors (who speak very little English) have enviable swaths of amaranth growing in full sun and full shade. I'm on the hunt for seeds :-)
    ...See More

    Native Plant Dormant Seeding with Mulched Leaves

    Q

    Comments (5)
    Crocus does well in a lawn, as does aconite. I'm thinking that galanthus (snowdrop) would also do well, but I've never seen it tried and the flowers are rather plain. Winter aconite and snowdrop are some of the earliest flowers in the garden, usually flowering slightly before the early snow crocus. All are short enough that they'll tolerate being mowed--the leaves will simply stay up longer. But you'd never be able to blanket spray an herbicide while the bulbs are active as it'll damage or kill the flowers. The bulbs are active during the green leaf season, through April, and again in October through December. Hyacinth is a bit late and a bit tall for the lawn, plus the paddle-shaped leaves are definitely going to stand out as the lawn returns. But if that's your bliss, it's worth a shot. Grape hyacinth would be a possibility if you can hold off on mowing until after the flowers bloom, and it'd be rather striking. I use it throughout the gardens.
    ...See More
  • Dan _Staley (5b Sunset 2B AHS 7)
    12 years ago
    last modified: 7 years ago

    I'll have the huge amount of dormant seeds competing with my native seeds, right?

    Yes. This is your issue.

    Dan

  • borderbarb
    12 years ago
    last modified: 7 years ago

    Re: worry about dormant seeds ... why not go ahead and sow the wild flower mix and see what happens this year. If the unatractive weeds overwhelm the pretty wild flowers, then go the smother/layer route.

  • Kimmsr
    12 years ago
    last modified: 7 years ago

    Laying down newspaper and then covering that with a mulch will aid in killing the "weeds" that are growing there and will help add organic matter to the soil. The newspaper and mulch does not "smother" the plants growing there now it deprives then of access to the sunlight they need to grow and without which they will die. You could seed right into the material you mulched with and as these native plant species grow, and the soil bacteria digest the newspaper, they will root into the soil under that mulch.
    Solarizing soil requires several weeks of good sun, about all of your summer, and will also kill off a good portion of the Soil Food Web which will then need several years to recover. Covering any soil with any plastic, because that so limits the exchange of air a good, healthy soil needs, is not a good organic practice.

  • anney
    12 years ago
    last modified: 7 years ago

    Kimmsr

    About this: Solarizing soil....will also kill off a good portion of the Soil Food Web which will then need several years to recover.

    Your statement above ignores a great deal of research, such as this information from the University of California. The reason for some of its beneficial effects have not yet been identified. Increased plant growth response. Plants often grow faster and produce yields of increased quantity and quality (size and appearance) when grown in solarized compared to nontreated soil. This phenomenon can be attributed, in part, to pathogen and weed control, but it is largely unexplained. For example, when soil apparently free of pests is solarized, increases in plant growth are still observed. A partial explanation may be found in a combination of mechanisms. First, because major pathogens and pests are controlled, it is likely that minor or unknown pathogens and pests are also controlled. Second, some soluble nutrients such as nitrogen (NO3-, NH4+), calcium (Ca++), and magnesium (Mg++) may be increased and made more available to plants in solarized soil. Third, beneficial microorganisms, such as mycorrhizal fungi, Trichoderma sp., actinomycetes, and some beneficial bacteria survive the solarization process or recolonize the soil rapidly. These in turn may contribute to a biological control of pathogens and pests and/or stimulate plant growth.

    Special Uses for Soil Solarization. Soil solarization has been used successfully on a large scale to control Verticillium wilt in pistachio orchards in California. Using both hand labor and plastic-laying machinery, the orchard floor was completely covered in plastic. Plastic strips were hand applied around tree bases and connected to a strip of machine-applied plastic between the tree rows with heat-resistant glue or by using narrow bands of earth to hold the strips down. The 5 to 10-year-old trees partially shaded the soil and plastic but not enough to prevent soil heating, which the trees survived with no visible detrimental effects. Although expensive, success of this method in existing orchards indicates the high potential of solarization to control some soilborne problems.

    Soil solarization has also been used successfully in Israel to control soilborne pests in greenhouses.

    Special Considerations of Soil Solarization. Soil solarization requires that soil be out of production for at least 2 months during the summer. To avoid losing a growing season, special attention should be given to crop rotations and sequences that allow solarization but also take advantage of the land before and after treatment. In the Imperial and Coachella valleys, where summer temperatures are too hot for most crops, soil can be solarized during summer and planted during fall or winter.

    Sensitivity to heat of plant pathogens, weeds, and other soilborne organisms differ. Some organisms will not be controlled by solarization and will require other control measures. This appears to be the case with sweet clover (Melilotus sp.) and some high temperature fungi in the general Macrophomina, Synchitrium, and Pythium. Conversely, some organisms difficult to control with soil fumigation, such as seeds of cheeseweed (Malv parviflora) and field bindweed (Convolvulus arvensis), are easily controlled by soil solarization.

  • anney
    12 years ago
    last modified: 7 years ago

    From the conclusions in the UC link above:
    Does soil solarization kill beneficial soil organisms? Populations of some beneficial organisms, such as Trichoderma spp. or actinomycetes, may be increased by solarization. Other important soilborne organisms, such as mycorrhizal fungi, may be decreased in the upper soil profile but not enough to lessen their beneficial action. Populations of some microorganisms, such as beneficial bacteria (Bacillus and Pseudomonas spp.) are partially decreased during solarization but afterwards recolonize the soil rapidly. However, populations of Rhizobium spp. of bacteria, which fix nitrogen in root nodules, are killed and must be reintroduced with seeds of legume crops. Survival and activation of beneficial organisms appear to play an important role in the increased plant growth commonly observed in solarized soils.

    It appears that of the important soil bacteria, only Rhizobium spp. is destroyed by solarization to the extent that they need to be replenished by planting legumes, probably with a nitrogen inoculator to most rapidly bring the soil back to its optimum bacterial balance.

  • dicot
    12 years ago
    last modified: 7 years ago

    I started a similar project about 8 years ago here, using almost but not completely organic methods. My two biggest regrets are not eliminating more of the bermuda grass right away, no matter what it took, and engineering my yard to provide the best possible drainage and tilth.

    {{gwi:140550}}

    {{gwi:140554}}

    My suggestion is that if you can, get a giant compost pile going simultaneously during this time using mainly deciduous leaf mold and inoculated with shovelfuls of your native top soil. Ideally, you would kill the weed seeds with a hot compost technique, yet maintain a large store of soil flora and organic matter for mixing back in the yard after whatever weed killing methods you use.

  • Kimmsr
    12 years ago
    last modified: 7 years ago

    Anney, If I read that right solarizing soil will kill of disease pathogens but not beneficial soil organisms, right? That is not going to happen no matter who wrote the article. Disease pathogens, Bacteria that cause disease, are generally tougher, hardier, then any of the beneficial bacteria.
    An article from the University of Georgia I saw some time back indicated the soil needed to be out of production for 8 to 12 weeks, about the whole growing season in Minnesota. Soil solarization may be of some benefit in Georgia and other southern states with a long growing season, but few of us up north will find enough sunny days to try that.

  • anney
    12 years ago
    last modified: 7 years ago

    kimmsr

    Yes, we have a longer hot growing season here than folks in Minnesota do, but even so, the solarization process in the summer takes away a lot of the growing time for plants that need hot weather.

    The link does not claim that solarizing the soil will spare beneficial organisms but that in the field tested, they quickly recolonize with the exception of nitrogen-fixing organisms. What I suspect is that probably most organisms are killed and some DO repopulate the soil quickly if the soil is otherwise healthy. Conditions need to be right for the repopulation of beneficials to occur, of course.

  • Kimmsr
    12 years ago
    last modified: 7 years ago

    If the soil is otherwise healthy is the key. If you already have a good, healthy soil then solarizing it would be of no benefit. Solarizing is only needed on soils that are unhealthy.

  • anney
    12 years ago
    last modified: 7 years ago

    Well, no, kimmsr, healthy soil can have invasive plants that are impossible to eradicate with other methods. I know this is your mantra, but it just isn't true. It isn't true about insect pest damage either. I think it's like anything in nature. Even with healthy soil we'll need to be able to accept some pests and some weeds and some less-than photogenic plants and not try to make a garden be perfect as many photographs would have us believe we can accomplish.

  • Dan _Staley (5b Sunset 2B AHS 7)
    12 years ago
    last modified: 7 years ago

    If the soil is otherwise healthy is the key. If you already have a good, healthy soil then solarizing it would be of no benefit. Solarizing is only needed on soils that are unhealthy.

    Puh-leez.

    Dan

  • dicot
    12 years ago
    last modified: 7 years ago

    If the aim is heat for sterilization, why not skip the 6 weeks of inactivity and get a garden torch (a lawn dragon or whatever) and fry the whole mess crispy? You can rent them at some places or a flame weeder plus the propane is still under $100 to buy.

  • anney
    12 years ago
    last modified: 7 years ago

    dicot

    I don't think a flame weeder would have the same effect. It would certainly kill off some surface weeds and maybe some surface microorganisms, but solarizing the soil kills everything several inches deep, the roots, insect pupas, and most of the bacteria and funguses that are causing problems. I recall reading somewhere that earthworms will burrow quite deeply into the soil to escape both heat and freezing, so they are not destroyed.

  • Kimmsr
    12 years ago
    last modified: 7 years ago

    "but solarizing the soil kills everything several inches deep"
    anney, that sytatement contradicts what you have been trying to say elsewhere and fully supports what I have been saying about solarizing soil. There simply is no way that solarizing is going to distinguish between the beneficial soil dwellers and the bad guys and kill only the bad guys, especially since most of the bad guys are meaner and tougher then most of the good guys.
    I am aware that there are some people here that simply cannot believe a basic premise of organic gardening that a good, healthy soil will go a long way toward curing the problems many people have in their gardens, because they have never gotten there.

  • anney
    12 years ago
    last modified: 7 years ago

    kimmsr

    RE This: anney, that sytatement contradicts what you have been trying to say elsewhere and fully supports what I have been saying about solarizing soil. There simply is no way that solarizing is going to distinguish between the beneficial soil dwellers and the bad guys and kill only the bad guys, especially since most of the bad guys are meaner and tougher then most of the good guys.

    Do you have problems with comprehension? Or do you just not read posts? I said this: The link does not claim that solarizing the soil will spare beneficial organisms but that in the field tested, they quickly recolonize with the exception of nitrogen-fixing organisms. What I suspect is that probably most organisms are killed and some DO repopulate the soil quickly if the soil is otherwise healthy. Conditions need to be right for the repopulation of beneficials to occur, of course.

    Some people are just fanatics with closed minds.

  • borderbarb
    12 years ago
    last modified: 7 years ago

    Since both bad and good soil organisms will repopulate after soil sterilization measures, what is the purpose? Weed seeds that might be killed can blow in from neighboring lands, and it seems that controlling weeds can be done in far less intrusive ways. The OP is in MN, so perhaps the subject of soil sterilization is moot. I think that my advice to the OP is on the laissez fair [lazy/hope for the best] order. Sow the flower seeds this year. If there is a problem with unwanted/noxious plants, then take more stringent measure. But chances are, that even in that event, there would only be 'islands' where more labor/time intense measures would be required. BTW - dicot's pictures are lovely. That's the look I'm hoping to achieve in a side yard with no water.

  • amy_harvestfaire_org
    11 years ago
    last modified: 7 years ago

    I think with all the combative language, we have missed an important part of this site: there are TREES there. So the effects of solarization will be substantially reduced. Solarization is mostly used to control soil diseases and nematodes that run rampant in parts of California, studies have shown it only effects about 2" of the soil in terms of sterlization of dormant seeds - it is not really what you need.
    Just scrape off whatever you can, get some black filter cloth - it blocks light but not water - and put it down, then starting building up some bew compost with whatever you can get your hands on - layer it onto the black cloth and try to get it about 12" deep. You can cut the cloth open in some areas to put in a larger addition, but be sure to remove the soil from the hole and dispose of it rather than mixing it into the compost.
    Your area will not be hot enough long enough to use solarization for weed removal and the lack of a heat containment below soil during solarization makes its efficiency just terrible related to the work and time required to do it.