Knowing where weeds come from, means we can set up the conditions where they will not take root.
To know this we need to look at weeds a little bit differently from the combative model. The “traditional” approach is to see weeds as the enemy. Something which needs to be attacked at every opportunity. Deny them life, destroy them. And, to be fair there are time to take this approach but it is not a good starting point. For a more on this Epoisode 127 of the World Organic News podcast would be a useful listen.
To understand weeds we need to understand the growth habit of the weed, its place in the ecosystem of the garden and what it is trying to do to assist the ultimate aim of Nature: no bare soil.
Where Do They Come From?
If we look at how the ecology of weeds works we will have a better idea. Think back to the end of the last ice age. As the glaciers retreated, bare soil was exposed to the light of day. Natural systems do not function well with bare soils. Erosion and so on are the consequences.
Weed seeds are all about us. They lie within the soil waiting to express their “weed-ness” into an environmental niche.
Why Do They Come?
They come to protect the soil in the most efficient manner possible. It’s not that Natural systems “make decisions” in the sense we do but after 4 billion odd years of life on this planet, sufficient evolution has occurred so that there is a seed for every occasion. We are attempting to create the niches ideally suited to the needs of our vegetable seeds. So if we dig, turn the soil, rotavate or plough, we are creating the conditions for weeds. The bare ground of the de-glaciated soils from 10 to 12 thousand years ago. Hence no-dig. I’ve covered how to set up a no-dig garden bed in module 101. By placing material over the soil, we are not creating the bare soil conditions where Natural systems will attempt to fix the “problem” we didn’t know we were creating.
Setting the Right Conditions
The actions of weeds, when seen from the soil’s point of view, are to cover it. Protecting the biology underneath. The great advantage of the no-dig method is against annual weeds. They come to cover the soil, we cover the soil and they have nowhere to grow. Now on a deeper level perennial weeds suggest a bigger problem. Things like thistles are annuals and can be dealt with by either setting the conditions where they will not grow or by dealing with them through their lifecycle.
If thistles are a problem, or any similar growth habit plant, they will respond to slashing at the correct time. Cutting a thistle before it has reached the flowering stage, will only result in the plant still flowering but at the level it was cut. The secret is to wait until you see the first flush of purple on a thistle flower within the patch. This points to the plant moving from growing to seed production. This is the critical time. It is now that a scorched earth policy is needed. Slash, cut or stamp upon each and every plant. What happens is this: the plant will not return to the growth phase and grow new seed heads. The seed heads produced to this point will have immature seeds that are not viable and the slashed material will form a mulch layer over the ground they were growing on.
The perennial weeds, things like ragwort, blackberry and lantana, need a different approach but again this is based upon an understanding of the ecology of the plant. They generally have a store of energy in their roots. This gets them through periods of grazing, damage and drought. They also hold soil in place. You can out compete them. With blackberry I’ve seen people successfully use chokos to out grow them and then graze them with cattle. The cattle love the chokos and trample the blackberries. Follow up slashing is required when they grow back. I’ve used goats and damara sheep to do the same thing by directing eating the blackberries. My preferred method for all three of the perennials mentioned, ragwort, blackberry and lantana is to slash and slash and slash again. Eventually the underground root stores are depleted, the plant dies and the ground is covered with a mulch.
They Still Turn Up!
Weeds will always arrive. Off your boots, from birds and on the wind.With a no-dig approach, they will be small in number. That means you can uproot them and leave them on the surface to rot down and become part of the bed.
The Right Mindset!
It all comes down to the right mindset. Understanding where they come from, why they arrive and what they are doing means we have a deeper understanding of the problem. They, in fact, cease to be a problem. They become clues to our soil health, what we need to improve in our systems and a resource to respond to and improve the current conditions.
Weeds will come, our understanding determines whether they will be a problem or another piece of information helping us to make good decisions.