Compost lamb's quarter and pigweed?

Farming Orcharding
#1

Can lamb’s quarter and pigweed be composted? Someone told me I should yank them all out and burn them but that seems like a waste of organic material. Also, I know the leaves are edible but I have way more than I need.

I’ve got a sea of dead stalks that have dropped their seeds last fall but are still standing in an area I can’t mow or till. I’m wondering if I can:

  1. frost-seed a cover crop straight into the stalks that can out-compete the weed seeds and hope the stalks eventually break down on their own.
  2. hand-pull all the stalks and try to compost them
#2

Personally I would go with choice #1: broadcast a cover crop in there and smother out the weeds. Just make sure you choose something that germinates early and competes well enough to overtake the weed seeds. Pulling them feels like such a huge waste of time I wouldn’t even bother considering that idea. :slight_smile:

#3

How big is the area? I find that cardboard mulching works really well to get rid of big areas of weeds. Our problem is mostly thistle! I get old cardboard from large retail outlets (like appliance stores or drug stores) and spread it out on top of the weeds. The cardboard needs to overlap so there is no light showing through and wetted thoroughly or else do it just before a rain. You can use rocks or heavy branches to hold down the cardboard if you are in a windy area. Leave it there for a couple of months and, voila, the weeds all die back and you end up with luscious black soil and tons of worms and other wonderful creatures under the cardboard. Then you can plant in whatever cover crop you want. Right now is an ideal time to do it when the stalks can be bent down, before the new weeds have started to grow.

#4

Thanks for the replies, guys. The area is nearly an acre so I’m leaning toward choice #1. I actually have been stockpiling cardboard but I wont have enough for that big of an area. I have a smaller patch of gout weed around the house that has been slowly spreading for a number of years so I think I’ll cardboard mulch over that this spring. I’ve never actually tried frost-seeding so we’ll see what kind of germination I get!

#5

I like to use silage tarp to cover large areas in order to keep them weed free, as cardboard over an acre can be a pretty challenging project! From an ecological standpoint, I don’t know if that’s the best way to utilize cardboard given the incredibly intense processes involved in producing it in the first place. Not that producing plastic is any better, but at least you can reuse it for years. On the plus side, I typically only need to leave the tarps for about 3 weeks to get rid of annual weeds, although it takes quite a bit more time to kill perennial weeds (especially bindweed and thistle).

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#6

Yeah I’ve had the same concerns about using UV-treated silage tarp and plastics in general. But they’re so cost-effective and just plain functionally effective for hoophouses and tarps and fencing and trays etc that it’s hard not use them. I’ll probably be getting some silage tarps for stale seed bedding and weed control when I get my garden going.

Unfortunately I can’t use it in this particular case because the acre has tons of trees and shrubs planted into it so I’ll have to outcompete the weeds with good cover crops. The Midwest Cover Crop Tool is telling me oats, oriental mustard, and red clover are good weed fighters and can be sown in April. I think we’ll still have some freezing/thawing cycles in April so if I hand broadcast maybe I can still get a good germination rate. Not sure how well those 3 covers work together but I guess I’ll find out!

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#7

I harvest the “wild greens” for the my restaurants and Toronto Market. I have sold them in my Waterdown market as well, but it is tiring constantly giving out samples and explaining why people should eat them. Chefs and a number of customers in Toronto know they are yummy and nutrient dense. I just bring them and watch them sell out.
The trick is harvesting at the best stage of growth (young) for best flavour and tenderness. That can be time consuming - but considering I don’t plant, water or weed them - they are probably no more work than a cultivated crop. I haven’t planted spinach for years - just pick the best of the “wild spinach” (lambsquarters) when it shows up. Turns out they are extremely drought tolerant. We don’t irrigate. We are mostly perennials. They were really important in the market mix last year!
Both Pig Weed (wild amaranth) and Lambsquarters need the ground to be disturbed to really take off. Once the ground cover is established there will not be any pig weed or lambsquarters. I actually like the stuff - and it does not grow in the established ground cover in my orchards.
You have fed a number of wild birds during fall and winter since the seeds ripened. Do you have poultry?
They might like to wander and snack through it and lessen the seed count by a million or two. I admire those plants’ amazing ability to reproduce.
“Tons of trees and shrubs planted into it…” (dried) plant based mulch is pretty effective at choking out pigweed and lambsquarters and the mulch also helps the perennials.
I am particularly fond of red clover for improving the soil and establishing a weed competitive ground cover. Combinations are good. Oats tended to be in my mixes for the first year of application since it comes up quickly and “nurses” the clover (so I was told - seemed to have worked). In our orchards the mix has shifted (on it’s own) from mostly red clover to other plants including other very useful perennials like yarrow, and violets from wild seed either breaking dormancy or blowing in.
A few clumps of comfrey in the perennial mix is always a good idea. The only plant that I have seen compete with comfrey is golden rod.
I don’t worry about the seeds - I let the plants just decompose on the ground - including when I actually weed them. There are so many seeds per plant - miss one plant and you still have 50 thousand seeds. I think it is better to understand it’s growing patterns and how to avoid making it easy to thrive rather than trying to eradicate it completely. Plus it is comforting to know - come the next drought I will still have something to eat.

#8

Thanks Babalink, many good points there. I think I’m going to hand-broadcast a mixture of oats, red clover and some mustard in early may and try and harvest as much of the lamb’s quarter as I can throughout the season but not let them go to seed in fall. I’ll also weed and cardboard a small section next week just to see what happens.

Good advice about not trying to eradicate it completely. Pretty sure I’d end up pulling out my hair along with the weeds. Though it is hard to picture the oats and red clover outgrowing what must be millions of seeds.

Very neat that you’ve got orchards! I’ll have to check out your website.

#9

Some thoughts on your cover crop choices.

Red clover has one of the highest success rates from frost seeding: good choice. Termination can be challenging so consider this before seeding it.

Oats are another excellent cover crop but I think you may want to wait until spring to seed them; grass seed usually only has a 20% to 30% success rate in frost-seeding and even mature oat plants winterkill.

Oriental mustard (being a brassica) will provide habitat for flea beetles. If flea beetle pressure is a concern, you may want to skip it. It might also be habitat for swede midge, but probably not for imported cabbage worm or cabbage looper.

The timing is wrong, but a note for the future: I find winter rye is an excellent way to put fields to bed: it germinates down to 4C and starts before most weeds in the spring so it is the best thing I have found to outcompete weeds. If you can wait until it heads in June you can reliably terminate maybe 90% of it with a single mowing too.

SARE’s Managing Cover Crops Profitably is a good reference with fewer species but much more detail than the Midwest tool.

#10

Thanks for the feedback Rob. I’ll hold off on the oats and mustard until spring and only seed the red clover for now. I’ll have to check out that book for some more ideas of what to throw into the mix.

The section of the field with all the lamb’s quarter and pigweed where I’ll be sowing oats/red clover/mustards is the area among the rows of trees that I can’t mow. I’m going to seed the sections between the rows of trees to pasture this spring. But it’s the spaces around my establishing trees (all heavily mulched) that need

  1. something to outcompete the weeds but that doesn’t get too tall or overtake my trees
  2. a nice established groundcover that I only have to lightly seed for the next few years

I like the idea of a nurse crop like oats that will help establish the clover but then winterkill. I guess that would leave me with a good clover groundcover around my trees but without the encroaching pressure of pasture grasses.

#11

Sorry for the slow reply.

Off the top I would suggest white clover as a ground cover you can’t mow. PRO: fixes nitrogren, reasonably easy to establish, takes heavy traffic once established, only grows 10 or 20 cm high. CON: organic seed expensive, bloat risk for ruminants (second only to alfalfa).

But maybe you are happier with taller plants like red clover. PRO: easiest to establish, fixes nitrogen. CON: I think I read somewhere you need to plow it in green for it to release its nitrogen for other plants.

Understorey perennial grasses are creeping red fescue and Kentucky bluegrass. Both are used predominantly for turf, so ask for low- or no endophyte varieties (sometimes marketed as “forage” varieties): the endophytes help the grass outcompete, but at a cost of reducing biodiversity and maybe the palatability for grazing.

#12

Those two, and bindweed, we always burn. Twitch grass and viable seed grasses, as well.