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