straw mulching w/out seeds?

so ive used straw to mulch beds in the past. the seeds left over in the straw always seem to present a problem. has anyone ever left a bail out over the winter and let it get soaked for a few months? (im in coastal OR so it doesnt freeze much, but gets loads of rain)... any thoughts on if this would spoil the seed heads to make a seed free mulch??
i can get bails of alfalfa hay that i would like to use to mulch my lettuce beds in a greenhouse this spring.
any thoughts or other ideas?

Patrick, I have left a bale of straw in my strawberry garden over the winter and through the next year. The seeds did sprout and the bale became green like a chia pet. The second winter I broke it up into "flakes" and used it as mulch/insulation around some potted trees. It had begun to compost and was brown and moldy. This spring I spread it around and it didn't seem to cause any problems.

At another location I used several bales as a weed barrier around a building. I broke the bales into flakes and laid them down like you would a brick patio, The seeds did sprout but never seemed to root in the soil below. The flakes kept all of the weeds down as I had hoped. But after a couple of summers they had rotted and become compost and I had to rake them up and put them elsewhere .

We have been using thick mulch of year old unsold/unused straw (the large 300kg rolls) from local farms for nearly 4 years to reclaim/dock kill areas of our property as well as winter mulch our fodder growing field and haveb been very successful.  It has usually been at least 1 year old if not 2, and well weathered barley or wheat straw originally grown for winter bedding on local dairy farms...  We still get some seed germination but its not particularly strong and in the larger areas we keep it down by the occasional going over with the brush cutter. We also mulch our raised beds in autumn (before winter weather, snow, etc.) after clearing using regular size bales - if we have planted the beds (e.g. onions, leeks, garlic, spinach, spring cabbage) we "fluff" the straw up, but still 12 inches or so thick.  If the beds are just being overwintered for spring planting we lay down the flakes/slices as others have mentioned.  The raised beds are easy to weed out any germinating seeds and they never amount to anything.

We have never cleared the straw away before planting, but planted through it in the beds - or in the case of field/row crops like beets, mangels, potatoes, field beans, corn, etc. we simply pull back the straw to open up a row, sow the seeds and tamp them in, then pull the straw back over them.  We haven't cleared any straw away for a few years, although we use our breeding trio of pigs (and any offspring) as well as our chickens, ducks and geese to go through our fodder field in autumn, then rake it over and roll out more bales on top of it.  It builds up great soil that is easy to work - and the critters also process huge amounts of with digging and stomping etc.

i can get bails of alfalfa hay that i would like to use to mulch my lettuce beds in a greenhouse this spring. any thoughts or other ideas?

- I wouldn't recommend using alfalfa hay or regular hay for mulching if you want to avoid seed germination - as I'm sure you know hay is cut with the seeds on whereas straw is the by-product of removing the grain (seeds) from the cereal.  So they will have many more seeds even if the hay is a couple of years old. If we do get any free or cheap old hay/alfalfa we use that as mulch/weed killer in our orchard, paddock (around trees) and tree nursery where germinating seeds aren't a problem as they eventually just add to the grass cover.

Best of luck!!!

Straw shouldn't have much for seeds as that's what they harvest and the straw/stalks are the leftover part. Hay is different and does indeed have seed heads which is why they use it to start grass sometimes instead of using seed. With straw, they use one machine to harvest the tops and do not like losing any as that's their big cash crop and then another machine to cut the straw which gets them a little more income.

Patrick,

I have used straw often and I do usually get a few stray grain seeds that sprout into little grass plants, but they never cause any harm and are easily pulled out.  I can't quite tell from your post, is your garden absolutely infested with seeds from your straw?  Is this something you can go over and pull by hand (my usual technique--I find that it does not take much time at all)?

If you are really getting a weed problem I can suggest a variation of the technique that I use.  I am a teacher and as such I acquire literally hundreds of pounds of paper at the end of a semester.  For a long time I had no idea what to do with this paper.  It was like I was creating academic toxic waste--I did not wanting my tests to get out and have students get easy access to the questions on my test.  I did not want to throw them away because I have actually seen students rummaging through old teacher waste piles looking exactly for these tests (I even had one enterprising student sell his old homework to a new student).  For the same reasons, I felt uncomfortable about sending it off to be recycled.  Now I take these papers (tests especially--a 3-page test stapled together is perfect) and lay them down on the surface of the soil, then pile the straw on top.  The two materials work really well together.  The papers block weed seeds outright.  The ground is shaded, moisture is retained, weed seeds that somehow manage to germinate in the darkness stand no chance of growing through that barrier and die, and rainwater seeps effortlessly through.  The straw adds a bit of bulk and holds the papers in place, adds to the light-blocking, moisture conserving and weed inhibiting effects quite well.  In fact, I have learned that while straw by itself is helpful in the garden, persistent weeds will still grow their way through.  And those pesky wheat or oat seeds that are causing you troubles might germinate, but they will never get their roots through my barrier.  By the end of the season, the paper has mostly decayed, and the straw is starting to rot at which point I may just leave it over winter or collect into a compost pile.  Even better is to compost on the bed itself--the paper and straw get reduced and the magic of compost is happening right in the garden bed with no need to spread out in spring--its right there.  

Chances are you don't have ready access to a bunch of tests like I do, but could you come up with something that could take the place of my tests?  Newspaper and cardboard come to mind, but if you get resourceful, I bet you can get a lot of perfectly good paper for free if you look for it.  Personally, I am liking this paper option even better than recycling.  The reason is that there is a surprisingly large energy bill attached to recycled paper and in this use of unwanted paper, I get an added use for the paper that ultimately stays out of the landfill (it stays in my land in the form of composted carbon materials).

I hope you can make use of this technique.  I absolutely hate weeding--the worst, most offensive part of gardening in my opinion.  Therefore I refuse to do it anymore, but then I don't have to--the test-plus-straw approach reduces my weeding to virtually zero.

Best of luck,

Eric

Eric Hanson wrote:

I am a teacher and as such I acquire literally hundreds of pounds of paper at the end of a semester.

What a great untapped resource and strategy, we gotta find a local teacher to supply us!

Ed,

You might actually be able to do this if you went to a school (I am betting a high school is better) and let them know that you want papers and will destroy evidence for would-be cheaters.  Teachers hate cheating and if you tell them you will take their mess away for free and destroy it, they might just load you up with a bunch of tests.

Eric