- EP284 Homemade Fertilisers & Their Benefits In The Garden: Nettle & Comfrey: Creating Natural Fertilisers for Healthier Plants

Transform your garden with powerful homemade fertilisers hiding in plain sight! This episode dives into the world of natural plant nutrition, answering listener Cian's question about nettle and comfrey teas.

Discover why these humble "weeds" might be your garden's greatest untapped resource. Nettle tea, packed with nitrogen, creates remarkably resilient leafy growth with glossier, darker foliage that naturally resists pests and disease. Meanwhile, comfrey provides the potassium boost flowering and fruiting plants crave. Together, they form a complete natural feeding system that nurtures both plants and the vital soil ecosystem beneath them.

You'll learn the simple process for creating these potent brews, when to apply each for maximum benefit, and how to recognise the subtle but significant differences between plants fed with natural fertilisers versus synthetic options. Beyond nettles and comfrey, we explore other free fertiliser sources you might be overlooking – from banana peels to grass clippings – and how the "chop and drop" method can build remarkable soil health with minimal effort.

The underlying philosophy throughout is clear: feed the soil, not just the plant. When you nourish the complex web of life beneath your feet, it rewards you with stronger, healthier plants that require fewer interventions. Whether you're growing vegetables, flowers, or maintaining borders, these sustainable approaches deliver results while keeping your garden in harmony with nature. Have a gardening question you'd like answered? Reach out and your topic might feature in an upcoming episode!

Chapters

• 0:00 Introduction to Homemade Fertilisers
• 4:20 Benefits of Nettle Tea Fertiliser
• 8:05 How to Make Nettle Fertiliser
• 11:25 Comfrey Fertiliser Applications
• 14:38 Other Household Fertiliser Options
• 16:30 Questions and Episode Closing

Transcript

Speaker 1: 0:12

how's it going everybody, and welcome to episode 284, master, my garden podcast. Now, this week's episode is a listener's question. I mentioned last week that keane o'reilly, who has moved into a new home two years ago and they're creating the garden of their dreams, he says, and they came across the podcast about a year ago and has been really helpful on on their journey, you know, to get in the garden of their dreams and upcoming projects for the garden include greenhouse and raised beds and so on and it's, you know, he says the podcast has helped quite a lot and so lovely to hear from you. Keen, and your question relates to homemade fertilizers and how to kind of use them within the garden. He says there's an abundance of nettles in the garden and that's, uh, that's not a bad thing because he gets the opportunity to make nettle tea and chat about, you know, the benefits, how to make it, and comfrey tea as well. He wants, wants to start making comfrey tea and you know we'll talk about how to do this and the benefits of it and how to use it, which is kind of his question. It's, it's um, how to make use of these fertilizers that he's creating and it's, I suppose it's a, it's a brilliant topic and it's a useful topic for people, and it's also one that in ways I've covered before on the podcast, not specifically relating to to nettle or comfrey tea, but the kind of the idea or the background of it still remains the same that what we're looking to do all the time is to create a healthy soil and that healthy soil, or we feed the soil, and that healthy soil is what feeds the plants up on top.

Speaker 1: 2:02

And from my point of view, there is no science to this in terms of you know, I don't. I'm not a scientist, I'm not a soil scientist, I don't know the ins and outs, I don't know the you know exactly what's going on in these, in this complex food web that goes on in the soil. But I do know one thing for sure that when you treat the soil well, that what goes on on top is certainly much more successful, much more healthy and, generally speaking, you're growing nutrient dense, resilient and better plants up on top. So, to answer Keane's question, I'm going to tie all this into the fact that we're you know, that we're you know we're looking to build siloed health all the time and not just use fertilizers as a there's something wrong here, let's feed. So it's a. It's more of a holistic view of it, I guess, and I suppose there's multiple benefits of both comfrey and nettle tea and other sort of homemade fertilizers, so we might talk about some of those as well.

Speaker 1: 3:09

And for me personally, I have used nettle tea on numerous occasions or nettle fertilizer on numerous occasions currently not using it, and the only reason for that is just in terms of time. It doesn't take a lot of time, but it's more time than I can give it at the moment, but it is and certainly was fantastic when I used it. It's very, very pungent. For anyone that has made it for keen, I'm sure you're seeing that it's extremely pungent. But what you do get is a similar response to what you get when you're applying seaweed, and seaweed is my go-to fertilizer. That's what I use on a regular basis. It's cold pressed seaweed and the reason I'm using that is because of the soil health benefits, but also the how much healthier the plants always seem when you're using something like seaweed. And I would have got the same response when using nettle.

Speaker 1: 4:07

You know nettle fertilizer. So that's kind of the, as I said, a the way I'm going to come at this. So, in terms of you know, we look at the two fertilizers, we look at how you make them and we kind of look at the benefits and they're very, very similar in some ways, but there's some little distinctions between them that are quite important. So, homemade fertilizers they're obviously very sustainable. So if you're like keen and you have these nettles in the garden, you're able to produce a quality fertilizer from those nettles and that is obviously sustainable. It's nettles have been used in organic you know organic production for a long number of years and there is definitely some benefits beyond the fertilizer element. So in terms of microbial life, it certainly improves the microbial life, as all organic matter will when you're adding it to the soil. That is, you know, key. As I say, we will come at it from this point of view that it's it's soil health number one that in turn gives you plant health up on top.

Speaker 1: 5:14

But nettle fertilizer specifically, it's a really high nitrogen, high in nitrogen. So you know, when you look at your NPK, it's very, very high in nitrogen. It's quite low in NP and it'll be kind of a mid-level in terms of K. So something that's really high in nitrogen is very, very good for leafy crops or crops at the early stage of growth. So, for example, leafy crops or crops at the early stage of growth. So, for example, leafy crops would include all the brassicas, your cauliflowers, your broccolis, your cabbage, your Brussels sprouts, your kale, anything that's putting on leafy growth up on top Really really useful for that. It's also useful for most crops when it's in its leafy growth stage. So even things like tomatoes in the early stage of the year when they're not putting out much flour, then it's you know, it's it's a. It's a brilliant fertilizer to drive that initial growth at the start. And again, because you're adding organic matter, you are feeding the soil as well.

Speaker 1: 6:12

I always find with seaweed and with the likes of nettle, that you get a really resilient plant up on top. So you end up with a plant that has a glossier leaf, a darker colored leaf and, I find, a kind of a tougher leaf, if that makes sense. So if you get your standard npk fertilizer and you load it on, I find you get a lot of growth. But it tends to be be if you felt the leaf of a tomato, just to use that as an example it tends to be a really, really soft growth and I find that that soft growth can be a little bit susceptible and less resilient than the hard growth. You know the leaf will be a little bit harder, a little bit glossier, has that dark look to it and just a tougher it's just tougher leaf, which means that it's less susceptible to diseases, less susceptible to pests and so on.

Speaker 1: 7:07

So nettle fertilizer high in nitrogen um, very, very high in nitrogen and good for leafy crops or for crops in the leafy stage, like the early stage of tomatoes and so on really easy to make. So how do you make it? You basically get young nettles. So the the really fresh, vibrant growth of nettles. You cut them at that stage, not when they're going to seed up on top, and you're not looking for big woody stems. So it's that earlier stage of growth. If you've cut nettles earlier in the year, you're going to get a flush back of growth again. It's that flush back of growth. That's absolutely fantastic, high in nitrogen. That can be used even as a chop and drop once there's no seeds on it, just use that as a chop and drop and again it's going to do the same thing.

Speaker 1: 7:53

But if you're making a tea out of it or a fertilizer of it, what you're doing is you're chopping it. At that stage, you're adding it to a bucket, you're adding in rainwater ideally into it, and then you're making sure that you submerge all the leaves under the water and then you close the lid on it, not tightly, you allow it to breathe slightly and you leave it for anything from one week to three weeks. And you leave it for anything from one week to three weeks, depending on you know, at certain times of the year, if it's warmer, it'll actually, I suppose, turn into fertilizer quicker, but at certain times of the year it might take three to four weeks, but at other times it might take a week. When you open that, it will be absolutely stink. It's a really, really, really pungent smell, but it's a superb high nitrogen feed.

Speaker 1: 8:43

At that stage, if you're going to start putting it through a watering can with a rose, then you definitely should strain it into. You know something that you're going to, like a bottle or whatever it is, or a can. If you're going to, as I say, you're going to put it out through a rose on a watering can, you should strain it because you will clog up your the rows on your watering can. But when you have this concentrated feed. Then you can dilute that, a kind of one to ten one part fertilizer to 10 parts water. It can be more, it can be less. You won't go too far wrong with it. It's not going to do any harm or not going to do any damage if you overuse it or underuse it. But roughly speaking, you're looking at one to ten and apply that as a root drench or as a foliar spray.

Speaker 1: 9:26

As a foliar spray, people will say that it has some, you know, fungicidal properties and some insecticidal properties. By using it as a foliar spray, I think it's more. Again, to go back to what I said, it makes. It makes the leaf kind of tougher, gives a little bit of tougher outer edge. There is some elements of of nettle tea and nettles that stimulate certain hormones within plants and one of those hormones releases chitin. So chitin it will be, will be again, it will be quite a specialist food that people will be aware of in growing circles that stimulates resilience in plants, stimulates tough leaves, and so I think that's what's happening, is that it's it's. It doesn't itself have antibacterial or antifungicidal or anti, you know, insecticidal properties. I think it's just that it's stimulating this chitin that basically makes the plant more resilient, and so it's, you know it's, it's given the the effect of insecticide or fungicide while not being those things, so it's hugely, hugely beneficial.

Speaker 1: 10:38

The other thing with it is that it is again mentioning it that it feeds the soil. So you know, once you get that, once you start feeding that into the soil, the soil life is is responding to that because it's it's natural, it's going to start taking it in and and converting it within the soil. So you're to have a multitude of benefits from using it. And, yeah, you can use it as a chop and drop once there's no seeds on it, or you can use it as a tea. So brilliant fertilizer. And when you have the nettles in the garden, keane, you might as well use them, and that's a brilliant, brilliant way of using them.

Speaker 1: 11:16

I did mention, though, that it's not very high in K. It has kind of a medium level of K, and then the flip side of that, then, is comfrey. So comfrey is quite good, for it's quite high in K and that's quite good for flower growth and developing fruit growth. So very, very similar, you know, very, very similar in terms of what you can do with it. So there are certain varieties. I don't personally grow it, but Bocking 14 is one that's mentioned a lot in organic circles to grow, as you know, as your your crop, for creating comfrey tea or comfrey fertilizer or for chop and drop, and it's a. It's supposed to be a really suitable variety for that. Again, as I say, I don't, I haven't grown it particularly, but I have seen it and I know that people in organic circles will use it a lot.

Speaker 1: 12:12

But the fact that it's high in k it gives you a sort of a counterbalance to the high n of the nettles. So to use the two of them in combination, you don't need to use them at the same time. But if you're using it in the earlier stages of, say for again as an example, a tomato growth, you use your nettle feed for the first couple of months and as flowers start to develop, you switch to your, your k and then alternate every second, every second feed, use one or the other, and you'll find then that that'll do a really, really good job because it's getting the plant, is getting everything it needs. It's getting the nitrogen to continue to push out leaf growth up higher and it's getting the k from the comfrey then to give you that fertilizer that's going to turn. That's going to grow your flower, that's going to turn into your fruit. So by combining them, it's very, very useful. So the comfrey is going to be useful for anything that that flowers and then produces. You know fruit or veg after that. So you're talking about tomatoes, squash, potatoes, peppers. You know any of those type vegetables within your garden. Also useful for a lot of your, your flowers within the garden, your perennials within the garden. And again, using it at the as it's coming to flowering stages is really, really beneficial.

Speaker 1: 13:24

You can, a little bit like the nettle, you can use it as a chop and drop as well, so you just allow the flush of growth to come. Then you just chop it, basically drop it wherever you want it around the plant and allow it to break down naturally into the soil. The method for creating the fertilizer is quite similar to nettles. You can you can add it to water. You use probably a little bit less water, but you can add it to water. You can also just put it into a bucket and allow it to break down naturally without the addition of water and it will create a liquid in there. You do need to strain it again if you're putting it out through a watering can that has a rose on it, but again, it's giving you that high k and like the nettle, like the nettle fertilizer, it is feeding the soil. So you're not just you're not just you know getting a plant benefit, you're getting a soil benefit which in turn, gives you healthier, stronger, better plants up on top. So I suppose, if you get the gist of what I'm saying is you're you're looking to feed the soil, and these fertilizers are superb additions to the soil life as well, and that, as I say, gives you these resilient plants or resilient plants up on top.

Speaker 1: 14:37

Other things that are useful you know around the home banana peels, really high in k as well. They can be simply, if you're planting, you know something like a tomato, put them in under the tomato plant when you're when you're planting it. They will add high levels of k and you can also mix them with water. I have never done that. I have often just dropped the banana peels, just chop them a little bit, drop them in around the base of tomatoes and really, really useful Anything that's fruiting, that's flowering. Banana peels are good for that, the likes of seaweed. Then, if you do happen to live close to the sea and you do have access to seaweed again, you can use that. You're feeding the soil. You can use that. You're feeding the soil. And you know there's other options as well.

Speaker 1: 15:31

For me here something that I do, uh, when I'm cutting the grass and I only did it last week at this stage of the year you're getting this really lush, vibrant growth that's really high in nitrogen. All I'm doing with that is tip up the box of grass right beside your borders and then put a sprinkling like an inch of it all across the borders, everywhere, and that'll break down and in a couple of weeks time when you go back, that grass will be disappeared. Now don't put three or four inches. It'll turn to sludge and if you get a really dry time, it'll go crispy first, but eventually that'll get digested by the soil life. And if you scratch back the soil in a month's time, two months time, and continually do this, you will see a really dark, humus, rich soil on top. So it's the same sort of a thing without the process of creating it.

Speaker 1: 16:16

So it's again using chop and drop. So there's more than one way to do it. The, the liquid version you know the keen has tried is a brilliant way and then it's useful. It's convenient, you know, in terms of going and feeding the likes of tomatoes or hanging baskets or whatever it is. It's a convenient way of doing it. The the chop and drop is really useful, then embeds and borders and so on. So loads of ways to do it, but again, the key to it is you're feeding the soil all the time, and when you're feeding that soil, though that that healthy, functioning soil, microbial life is basically driving up healthy and resilient plants up on top, and so that's that's what we're all in for, so kind of hope.

Speaker 1: 16:58

I answered the question. It's, um, the combination of the two is good, though, because you have the high nitrogen from the, from the nettle, and the high k from the comfrey, so you're getting the best of both worlds there. Both of them are going to be healthy for the soil, both of them are going to be good for the soil and very good for, you know, for for driving out the leafy growth and then, later on, driving out the flower and, in turn, fruit, fruits, and yeah, as I say, in combination they're they're a brilliant, brilliant combination. For any other listeners who are listening in, that's a, you know, question from keen and glad the the podcast is helping you. Anyone else that's listening that has questions, that has something that they'd like to know a little bit more on, just shoot me a, as I say, an email message on instagram or whatever the case may be, and I'll do my best to cover it in the coming weeks. And that's been this week's episode. Thanks for listening and until the next time, happy gardening, thank you.