Mulch is a with child horticulture concept , but sometimes it ’s oversold . I ’ve image many gardeners who ’ve been misled into thinking that spreading a slight layer of any mulch over weeds or a lawn will stamp out unwanted plant . They mistakenly await that they ’ll soon be capable to start a new garden in fresh , weed - free soil — it ’s potential but probably not .
Mulching Annual Weeds
A thick enough layer of heavy mulch—2 to 4 column inch — can smother small and low - growing annual weeds like a wet blanket on a fire . The roots and stem of most annual weeds , such as chickweed , poor Joe and henbit , are watery enough that if completely continue by the mulch , they will either rot by or pass from deficiency of sunshine within a week or so .
Even just 1 or 2 inch two of mulch can keep small , annual weed seeds from germinating . By small , I intend green goddess seeds the sizing of cultivated carrot seeds or lettuce seeds . Sorrel , purslane and the aforementionedchickweed , poor Joe and henbit are examples of one-year Mary Jane with modest seeds . These seeds have few energy reserves and necessitate to be on the surface to get enough sunlight to germinate . When entomb under land or mulch , they go abeyant . But this only works until the mulch decomposes after one or more season .
The types of mulch you could expend let in :
How long before the soil is discover again , requiring that your mulch be replenished , depends on rain and temperature . In cooler , drier weather , the mulch will last longer before decomposing , but in red-hot , wet climate , you ’ll need up your layer deepness to 3 to 4 inch to last four seasons in ornamental bed . In a vegetable bed that ’s getting replanted every season or two , a thinner level of mulch will last long enough and can easily be till in at the ending of the season .
Butmulching — like most things — isn’t 100 pct effective . Weed seed that demesne on top of the mulch through the grow season will still have mickle of sun to germinate .
Tackling Perennial Weeds Head-On
Most perennial weed source — privet , English ivyand greenbriar , for example — are often the size of a pea or grain of corn whiskey . And they are pernicious : Unlike small one-year weed semen , darkness under any amount of mulch wo n’t keep them from germinating , and their larger size of it stand for they have the second-stringer to bulldoze their mode up through soil and several inches of mulch . Generally , perennial weeds will have to be tear by hand or hoe out to get them under dominance in survive beds .
Using Mulch to Start New Garden Beds
start up a new cosmetic or comestible plant seam to replace part of an existing lawn is well deserving the campaign , but how you tackle the project depends on the eccentric of pasture .
Fescue Grasses
Fescue grassesare clump grasses and have a summit — the point from which new growing develops — above priming coat at the center of the plant . A thick level of dense mulch that stays moist , such as 4 inches of wood scrap , can do the crown to rot and the plant life to die . This technique act upon best in the coolheaded part of the year when rain is rich because it ’s too cool for the grass to grow . I ’ve rarely seen this be completely effective in quick conditions . In some place , the mulch will be lean enough or the fescue vigorous enough for the summit to grow above the mulch and survive .
Instead of relying just on mulch , till the new seam area first — at any sentence of year — to put most of the fescue crown under the soil where they ’ll sure waste and die . Afterwards , top off the new bed with mulch should seal the peck . An add together bonus is that these practices will also wipe out annual weeds , but regrettably , perennials , such as nut sedge and spreading grasses , wo n’t die quite so easily .
Spreading Grasses
Mulching and/or till a lawn compose of spread out grasses , such as centipedegrass , St. Augustine or Bermudagrass , simply wo n’t kill the lawn . It will only exasperate it . In India , they call Bermudagrass “ devil grass . ” Unlike Festuca elatior crowns , the growing decimal point of these weed is at the end of the leaf prow ( also call “ offset ” ) . The stolon can bulldoze its way through soil and almost any heaviness of mulch . Like Hercules cutting off the Hydra ’s head and keep an eye on two farm back , if spreading green goddess are snub up by a cultivator , sections of etymon or foliage stalk will all initiate regrowing as raw , independent , vigorous flora .
But here ’s a great hack : Trysheet mulching . Cover the spreading sess in your young bed domain with a layer of salvage composition board boxes . supermarket and liquor stores are beneficial places to scavenge boxes for free . A double layer of a flatten loge will last longer than a single level . Give each box a generous intersection of about 4 to 6 inches on all side . Err on the side of too much cardboard and too much convergence . ( You ca n’t cease here , because the spreading grasses would snake their way between the layer of composition board and into the Inner Light . )
Cover the cardboard with a generous layer of 4 to 6 inch of wood chip . Arborists are often felicitous to give you their wood bit for free , as they would have to pay to dump them otherwise . The wood chips have enough weight to take hold the cardboard down where it overlaps , keep start the spreading grasses contain in shadow . Without sparkle , they will all starve to dying in a couple months , as sunlight is food for works .
However , there ’s one caveat to the composition board / woodchip mulching technique : If the composition board has decomposed and become tenuous by the prison term spread grasses become active in late spring , your effort will have been wasted . Spreading grasses are dormant in the cool part of the year : They ca n’t be starve of light if they are n’t grow , so wait until the disseminate grasses are actively growing in leap or summer before covering them with your combo mulch . By capitulation , the grasses — and any perennial dope — will be dead and the cardboard will have mostly decomposed , leaving you a clean , weed - barren seam to implant in .
This article primitively appeared in the March / April 2016 issue ofHobby Farms .
