I’m sure that most people will agree that weeds are incredibly frustrating and tedious to deal with. I feel like I just can’t stay ahead of the weeds in some of the public spaces that I maintain. I’ll spend hours clearing out the weeds from an area, only to look at the same area weeks later and see … more weeds. Weeds grow and reproduce quickly, they establish a firm toehold very quickly, and they take resources away from the plants that we actually like. Weeds also attack our spaces in different ways, not all of them aboveground. Weeds are the plants that will walk away from a cataclysmic event, unscathed and probably happier for the experience.
Staying ahead of the weeds is critical. When it comes to controlling weeds, there isn’t one single way to beat them. The best way to control weeds is to chip away at the entire weed cycle. The principle is called “many small hammers”. The idea is that instead of using some single, big control measure on weeds (although single and big are one of the hammers), you need to chip away at them from a whole bunch of different angles, using a variety of strategies.
A big part of this strategy for dealing with annual, seed-setting weeds is to gradually work to reduce the weed seed bank, or the weed seeds that are within the soil. The first step is to try and prevent the weeds from setting seeds and putting more seeds into the bank. This is referred to as “seed rain”. Since you don’t always know which weeds are going to set seeds, or when they are going to set seeds, it is usually a good idea to remove the weeds entirely from the site, as much as possible. Early weed control is always the best strategy. The simplest form of weed control for annuals is pulling them or cutting them off from their roots.
The next line of defense (and attack) occurs on the soil surface. Predation is where seeds are eaten and destroyed by things like birds and insects. This is mostly out of our control (unless you are raising either of those types of creature), other than by providing an environment that is friendly to the wild types of these creatures, and by not discouraging them from doing their thing.
Just below the surface of the soil, there are a number of weed seeds. If you work the soil shallowly, the shallow weed seeds are encouraged to germinate, hopefully all at once. This allows these new, tender seedlings to be quickly and easily controlled, while avoiding bringing the deeper seeds to the surface.
As mentioned, deeper in the soil, there are many other weed seeds. In theory, the further a seed is from the soil surface, the less likely it is to 1) germinate, 2) reach the surface, and 3) produce a viable plant. Weed seeds also have a limited lifespan, although that length of time varies. Theoretically, the longer a seed is in the soil, the higher chance it has to rot, decay, and break down and therefore not germinate. By limiting the amount of deep disturbance, you can potentially avoid bringing deeper seeds within range of the surface. Alternatively, occasionally working the soil deeply can bury some seeds away from the surface.
Of course, controlling any weeds that grow is important. Controlling any weed when they are younger, smaller, and more tender, before they are firmly established, is best. How best to control weeds can depend on the weed species. As mentioned earlier, an annual weed can be pulled or killed by cultivating/hoeing, but some weeds actually multiply when you cut them up, or if you leave pieces of them behind. This requires careful, and often repeated, removal efforts.
Perennial weeds need to be attacked early and then regularly so that they are weakened before they can get bigger and stronger. Perennial weeds tend to have a lot more to them than what you can see above ground, so you want to make sure you remove any aboveground and belowground parts as best as you can. Stubborn patches of perennial weeds like quackgrass and Canada thistle may be carefully treated with a non-selective herbicide, provided there are no other plants of value around them, or those can be protected.
It is important to carefully consider the long-term effects of anything that you apply to the soil and plants, as well as ANY product that you might apply. Seemingly “safe” products or mixes/remedies can take things in a different direction than you might like, with wider reaching effects than just your space. Some products may not stay where you put them, eventually leaching, or leaking, out of the soil, ending up in waterways or other places where they cause unintended harm. Some non-herbicide methods of controlling weeds can kill the weeds, but also make the soil unable to support the growth of any plants, which is the opposite of what you want. If you have a recurring problem, try to identify where the weed is weakest and come up with a strategy to attack it in a safe way. Keep track of when activities are carried out in case there are issues later that need to be identified or linked.
In some spaces, using barriers (such as plastic or semi-permeable fabrics) on top of the soil can slow or stop most weed growth. Using organic mulches, like bark mulch, can also help to slow weed growth, as well as making plants more competitive, as they conserve moisture and keep things cooler.
Growing different types of plants lets you mix things up. Crops vary in terms of how competitive they are, or how they grow compared to other crops. This opens up your weed control options. For example, potatoes are hilled one or two times in the early season, which controls lots of the early weeds, but then they grow quickly and close up the gaps pretty tightly, crowding and shading out weeds. Other crops grow differently, so you can work between the rows more easily. Alternating between different types of plants gives you options.
As mentioned, some of the hammers you control; others you don’t. However, they all help. Guess what? If it’s a day that ends in “Y”, it’s Hammer time!