Stocking the Seed Bank

Making your Own Weeds

I'm concerned over the quality of weeds at the Grange Garden. Sure we have a nice assortment of the usual suspects: pasture grasses, lawn grasses, sorrel, hawkweed. ... but I've become spoiled by the chard, tah soi, calendulas, poppies, columbines and other goodies that come up in my garden at home. I'd like to improve the seed bank in our soil.

The soil seed bank includes all of the viable seeds stored in your soil. The prevailing notion for managing seeds in the soil is to empty the bank - don't let anything go to seed. When you think about it, emptying the seed bank is probably impossible. We have immense weed-free farms. By now we should be hearing about farms where the use of herbicides is falling because the seed bank is bottoming out.

The math confirms the near impossibility of maintaining an empty seed bank. Weeds produce so many seeds that you can prevent 99% of the weeds that germinate in your garden from going to seed and still not significantly reduce the seed bank in your garden.* Not to mention what the wind blows your way.

Experience shows the wisdom of making a serious effort to prevent weeds from going to seed. Most seeds germinate the first year after falling. Minimizing the short timers can reduce the biomass of weed seeds coming up in the garden. If this isn't true then farmers sure have been wasting a lot of effort.

In the spirit of improving the class of weeds we'll be hanging out with, we scatter cheap seeds and/or free seed throughout the garden, with abandon. We get some of our cheap seeds in the herb section of the Food Coop. It's a little known fact (in fact it's a bit of a trade secret and I hope you will keep this to yourself), but some of the seed-like herbs are in truth real seeds, and you can plant them in your own garden at a greatly reduced price.
In one of my landscapes we recently planted a Cilantro cover crop on a bank, five or six feet wide and over twenty feet long. For slightly more than the cost of a seed packet from your favorite seed company, we purchased a half a pound or a pound – whatever it was, it was enough seed to make a frighteningly thick stand of Cilantro. Not thick enough to lift the soil up when it germinated, but close.

The Cilantro so thickly because I underestimated the germination power of the seed. In the past I had lukewarm luck with sowing Cilantro seed from the Coop. I had been sowing it under less than ideal conditions when someone who was doing a good job planted it, it went nuts.
I'll eat a snail (cooked of course) if any weeds worth speaking come up through all of that Cilantro, in the recent future.

Good luck looking for Cilantro seed at the Coop. You won't find it. At least not under that name. Cilantro is two herbs in one, but only in the US. Everywhere else it is called Coriander. The leaves make a fine salad and salsa green, and the seeds make a piquant Asian/ Mexican spice.
Another fabulous cheap seed is Chamomile. My theory is that the ripest seed falls to the bottom of the jar where it forms a layer of detritus that is unsuitable for t4ea unless you use a coffee filter on it. To get to the seeds, you could find a gallon sized bag and carefully remove the ninety-eight percent of the contents that consists of intact flowers. Or you could buy all of the contents of the jar, and drink lots of Chamomile tea until you bottom out. Or you could turn the jar upside down and shake it until the seed rises to the top. Be sure to leave the lid on when you are doing this.

We planted some Dill and Caraway seed to see what happens.

Let some of your vegetables go to seed in your garden. Let most of your favorite plants go to seed, but be careful, a little seed can go a long way, as you may have already gathered from my experiment with the Cilantro. Exercise restraint and caution when introducing new weeds to your garden. Don't blame me if you introduce a monster nuisance into your garden – I warned
you.

* http://www.cropsci.uiuc.edu/classes/cpsc226/Lecture/seedbanks2/seedbanktext.cfm