The organic gardener is literally spoilt for choice when it comes to making our own homemade plant fertilizer. However, there’s always a particular ingredient that grows naturally all over the place which we can use as the main ingredient.
And that would be weeds!
Although weeds can have a negative impact on your vegetable garden if not controlled, they can also make a potent fertilizer. And to top things off, they’re absolutely free!
This article will focus on converting weeds into a powerful liquid fertilizer, or “weed tea”. You can dilute and apply this fertilizer directly to your plants, or use it as a foliar spray.
Why we use Fertilizers
Weeds are an invaluable resource to natural and organic gardeners. They can be used for a number of different things in the garden.
Generally speaking though, what we’re doing when using weeds in the garden to our advantage is recycling the nutrients and energy which they have stored in their biomass.
I sometimes think about why we should be creating fertilizer to begin with. If we’re truly trying to learn from and mimic nature, then creating such a fertilizer to begin with seems counter-intuitive.
Ideally, our soil would already have all the nutrients it needs from years of building it with organic matter and accumulating a good level of humus in the soil.
However, the difference between our vegetable garden and nature is that we generally demand a lot from our vegetable garden, and in particular our soil.
If we’re constantly growing our food and not replacing the nutrients which we borrowed from the soil, we’ll eventually deplete that soil of its nutrients. Then, future crops will suffer from a lack of these nutrients.
So by making your own homemade plant fertilizer, you can replace those lost nutrients and minerals. Other ways in which you can replace the lost nutrients are by adding compost and mulch. And by adding organic matter in general.
However, we should always return the nutrients and minerals we borrow back to the soil. Only then can the practice of vegetable gardening be sustainable.
If you’d like to learn how to make “living” soil in your garden or farm, checkout this article on how to do just that.
A Quick Word of Warning
Before we start, remember that different weeds will have different levels of nutrients, including macronutrients Nitrogen (N), Phosphate (P), and Potassium (K). This means that, unless you get sophisticated and get your finished weed tea tested in a lab, you won’t really know how much of each nutrient you’re actually getting.
This is okay though, as long as you’re aware of this and monitor the plants you feed. Normally you would only be feeding your plants in the growing season about every two weeks. Just keep an eye on them to see how they’re tracking.
You might also want to experiment with different types of weeds, as each will have different benefits and levels of nutrients.
Another thing to remember is that if your soil pH is too acidic or alkaline, certain nutrients will be locked-up and unavailable to your plants, no matter how much fertilizer you use. Depending on what you’re growing, this may or may not be an issue.
So if you notice your plants aren’t responding to your weed tea, test your soil pH and adjust it as necessary (for example if too acidic, add lime; if too alkaline, add sulfur).
Lastly, remember that too much of a good thing is not always a good thing. And when it comes to fertilizers, this couldn’t be truer (is that even a word?)
By adding large amounts of liquid fertilizer, you could burn your plants or be polluting your soil, which can have devastating effects on your crops. So make sure you dilute the fertilizer to the recommended amount and apply it with care. And remember to watch your crops for any signs of stress.
Now without further ado, let’s get to it!
Steps to Make Your Own Homemade Plant Fertilizer
Follow these steps to create your own plant fertilizer using weeds (a.k.a weed tea):
1. Grab Yourself a Good-Sized Bucket
I normally use a 20L (5 gallons) bucket like the one in the picture above, but I have also used a larger drum.
It should be large enough to fit all of your weeds after compressing them down a little to about halfway or three-quarters of the bucket full.
2. Gather all of Your Weeds, Roots and All
Unless you’re experimenting with one particular species, aim for a variety of different weed species. That way where one weed falls short of a particular nutrient, another weed may fill that gap.
Generally, you want to pick your weeds before they have flowered to avoid adding the seeds to the tea and later spreading them around your garden.
Unless this bothers you, don’t worry too much. Seeds will always be blown-in by the wind, brought in by birds, or washed in by rain. True, you will have fewer seeds if you’re careful to not add them once they have produced seeds, but you could also strain the liquid to remove most seeds (depending on how fine your strain is of course).
3. Shake Off Most of the Dirt From the Roots
Some dirt is fine, as you’ll be inoculating the tea with bacteria from your garden. Just try not to put in too much so the main ingredients are the weeds and water.
4. Chop up the Weeds as Much as Possible
This is an optional step. However, by chopping the weeds up, you’ll make it easier for the bacteria to break things down.
I use a half-sawn and sharpened shovel which is a perfect tool for the job, and doesn’t break your back!
5. Fill the Bucket with the Weeds
Fill the bucket with the weeds, then push them down a little. Don’t overdo it, just enough so it’s nice and compact and you have some room at the top of the bucket.
6. Place the Bucket in it’s Final Position
Before adding water, it’s a good idea to place the bucket in its final position. It will be easier to move it now rather than later when it’s full of water and weeds!
You might want to put the bucket away from any place or anyone who might not appreciate bad smells. Technically, if you keep the weed tea aerated by stirring it every day it shouldn’t smell. However, it might not always be possible to keep it aerated, and may start going anaerobic (which brings on the bad smells!).
Also, try to put the bucket in a place that is out of direct sunlight.
7. Place a Brick or Large Rock on the Weeds
This will help to hold them in place and will assist in extracting the minerals from the plants. However, this is not essential and will work just as well without it.
8. Fill the Bucket with Rainwater
If you don’t have rainwater (why not?!) you could fill a bucket with tap water a few days before starting out, to allow the chlorine to evaporate. Otherwise, chlorine could interfere with the bacteria.
But if all you have is tap water, you’re like me and aren’t the most patient person, just use tap water.
9. Give it a Good Stir
Every day or so, give the water a good stir and poke the weeds with a stick to oxygenate the water as much as possible.
Try to stir as often as possible a few days to a week before you intend to use it, to reduce the number of anaerobic bacteria and increase the aerobic kind.
In saying this though, I’ve used weed tea while it was anaerobic and I didn’t experience any issues (except for my family members complaining of the smell and running back inside!). It’s a good way to have a peaceful garden as no one will want to come outside 🙂
However, just know that applying it while it is anaerobic may make your soil slightly acidic. And as with anything which has gone anaerobic, just be extra cautious when handling it. Apart from the obvious safety precautions, be sure not to get any of the stinky stuff on your hands, as you’ll have a hard time getting rid of the smell!
10. Cover the Bucket
Cover the bucket with some kind of netting to allow oxygen in, but keep rodents out.
There’s nothing like coming out to check on your weed tea only to find a dead mouse in it!
You can also place a lid on the bucket if you like, just make sure it’s not sealed tight.
11. After About 4 to 6 Weeks, the Tea will be Ready for Action!
When you’re ready to use this super plant fertilizer, dilute it to about 1 part tea to 10 parts water, to avoid burning your plants. And as mentioned earlier, use a fine strainer if you’re concerned about weed seeds. Some small seeds may still get through though.
Weed tea can also be an excellent foliar spray for quick absorption into your leaves. This can work wonders to remediate certain issues with your plants when they show discoloring of the leaves.
Although, this would only be a quick and temporary solution to help your plant or tree along while you fix the issue with the soil.
My Meyer lemon tree, which lives in a pot, had yellowing leaves once, and before giving the soil conditions much attention, I used my stinky weed tea (which was well and truly anaerobic) as a foliar spray, where I thoroughly sprayed the affected leaves a few times over a few weeks. Within no time the leaves started greening again!
Final thoughts
Weeds are an excellent resource to use in the garden. By following this recipe for creating your own homemade plant fertilizer from weeds, you’ll have a powerful yet natural fertilizer at your fingertips.
Just remember to not overfeed your plants, as too much of a good thing isn’t always good, and can in fact become a pollutant.
Finally, remember that you should always strive to build and feed your soil with organic matter to create a good amount of humus. Fertilizers are great, but think deeper and long-term when it comes to soil building and fertility.
After all, it’s the life in the soil that helps plants thrive. Here’s the link again to the article on How to Make Living Soil.
