How To Make Your Own Plant Food

As readers of this blog will know, I have loads of plants in containers – well over 100! The down side of this, is the loads of watering and feeding they all need. I spend several hours each week, mixing plant feed into my watering can, to feed my salvias, achillea, clematis, roses, et al. Don’t get me wrong, I don’t mind the time spent doing this, but I do begrudge spending oodles of money on plant food such as Tomorite. I’d much rather spend it on plants! So I thought it was time to explore how to make my own plant food.

The result is several recipes which I think are well worth a try. Not least because they’re not only free to make but they’re easy too!

Read more: How To Make Your Own Plant Food

How to Make Plant Food

• Comfrey Feed
• Borage Tea
• Nettle Feed
• Grass Clippings Tea
• Green Tea
• Egg Shell Spray
• Urine

Comfrey Feed

Comfrey has very deep roots. These enable it to extract large quantities of nutrients from far below the soil’s surface. Nutrients other plants can’t reach. Comfrey stores these in its leaves. So a ‘tea’ made using the leaves is a brilliant source of goodness.

It’s rich in potassium, which is good for enouraging flowers and fruits. Tomato or gooseberry growers, this one’s for you! However comfrey is more than just a potassium-packed powerhouse of a plant. The nitrogen content in it helps with green leafy growth. While the phosphorus in its leaves will help plants stay vigorous and fight off disease and pest damage.

The recipe for making comfrey tea – which you then use as a soil drench or as a foliar spray – is pretty easy.

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Basic Technique

• You want a well established plant – as you want it to have a good deep root system that’s accessed all those lovely nutrients.
• Cut back a chunk of the plant (it will quickly grow back). It’s best to wear gloves, as the leaves can irritate the skin.
• Remove the stems and flowers – you just want the leaves. (The stems are good for your compost heap.)
• Chop the leaves up and pack them into a large plastic container with a lid. (You’ll need a lid as things will get very smelly!)
• Weigh down the leaves with a brick, add enough water to cover the leaves, put the lid on the container and wait.
• After about 3 weeks the leaves will break down and you’ll have a smelly brown liquid.
• Collect this and store it in a container with a lid – an old plastic milk carton is good.
• That’s it! Couldn’t be easier.
• When using the comfrey liquid you will need to dilute it at a rate of at least 10 parts normal water to 1 part comfrey liquid. If you don’t do this you will harm your plants you’re trying to so lovingly feed! As a rule of thumb, the darker the liquid the more you may need to dilute it. Diluted it should look like weak tea.

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The downside of this recipe is that you need to have comfrey growing in your garden, and it can spread. Those deep roots are tricky to get rid of once they’re established! And because its whole benefit comes from the fact it puts down a deep, elaborate root system which taps into all those nutrients, you can’t confine it by growing it in a container and get the same nutritious effect.

So if you already have comfrey in your garden, or have a lot of space and a scrubby corner that you aren’t precious about where you can grow it, go for it. But I’m not sure I’m going to introduce it into my garden. Not without trying some other homemade plant feed options first!

Borage Tea

Borage is a wonderful bee-friendly plant. Indeed it’s one of my recommendations for a bee friendly garden, attracting and sustaining these vital pollinators over its lengthy blooming period.

The flowers are edible too, and have a taste a little like mild cucumber. So they’re a good addition to my evening G&T!

Like comfrey, borage has deep roots. These draw up concentrates of nitrogen, potassium, and other micro-nutrients into the plant’s leaves and flowers.

How do you harness these nutrients to make plant food? Easy peasy. The technique is pretty much as per comfrey feed. Add as many borage leaves and flowers to a container as you can, fill with water and cover with a lid for two weeks. Then strain the liquid and use it, diluted with ten parts water.

Note, if you’ve borage and comfrey in your garden, add a bit of borage to your comfrey when making your comfrey feed, the end result will be an even better all purpose fertiliser.

How to Make Plant Food from Nettles

While nettles may not be as pretty as borage, and I certainly haven’t tried them in my gin, I’m very happy to have a patch of nettles in the garden. Not least because as Mr F-W keeps reminding me, they are absolutely brilliant for supporting butterflies in the garden . Nettles in particular are perfect for the caterpillars of small tortoiseshell, red admiral, comma and peacock butterflies.

For this reason I have a healthy clump growing in a corner. In addition to being brilliant for butterflies, nettles are also a great base material for a feed. The good news is that you can use much the same method as the one for comfrey and borage to make a nettle-based plant feed. You must dilute it in exactly the same way (10:1). But even with that dilution, don’t use it on very young plants or seedlings – it will be too potent for them.

Nettle-based feed is rich in nitrogen, good for encouraging leafy growth. Nettles also have some other nutrients, so they make a good general feed. Timing-wise, nettles are most nutrient rich in the spring, make your feed then.

Grass Clippings Tea

If you are making your own plant food to give a nitrogen boost to your garden and you don’t have or want nettles but you have a lawn, don’t despair, grass clippings are a brilliant alternative.

Grass clippings tea involves broadly the same technique as we’ve already covered but with a few tweaks.

• Fill a large container about one third of the way up with grass clippings.
• Don’t just cover the clippings with water, but fill the container to the top with it.
• Put a lid on the container, or if you don’t have one cover with a cloth.
• Allow to stew for two weeks and then it’s ready to use on your plants.
• The dilution is slightly different too. Dilute the grass clipping tea with water at a ratio of 5:1

Green Tea

While I may not be tempted to drink the previous mixtures, I quite like green tea (though I prefer traditional builder’s if I’m honest – with a biscuit of course!)

The good news is plants like green tea too. Green tea fertilizer can give a nitrogen boost to increase your plants’ leafy growth.

The only thing to bear in mind is that if you use it too often it will apparently raise the pH in your soil. But as a short-term boost to your plant’s growth, it’s a great, free and easy feed. Get a litre of boiling water, add two green tea bags. Let it brew, and then leave it to cool. Water your plants with this mixture about once a month.

If you want to do all your watering with this mixture without affecting your pH too much, then make a much more diluted version. Say two gallons of water brewed with a single tea bag.  

Egg Shell Spray

If your plants aren’t growing as fast as they should, have curling leaves or browning growth tips, they may have a calcium deficiency. But don’t panic, you can easily knock up a spray to tackle this using egg shells.

Egg shells have lots of calcium in them. To make a spray with them, you need a gallon of water and 20 egg shells. Put the shells into the water and boil the mixture for 10 minutes. Then leave everything to cool overnight. Next day, strain the shells out of the water and store it. Spray it directly onto your plant’s soil (not the leaves) every few weeks. I’ve not tested this out but apparently it works well for roses. 

Urine

With three sons I was forever telling them off for weeing in the garden when they were growing up, but it seems I needn’t have bothered!

Human urine is apparently one of the fastest-acting, and most effective sources of nitrogen, phosphorous, potassium and trace elements for plants.

I know it’s not the most appetising plant food, but if you think about it, it comes in a handy liquid form and from an economy point of view there’s no denying we all have a free ready supply of it all year round!

I know what you’re thinking – I’m thinking it too – the smell!! But if you use it when it’s fresh, you’ll avoid this problem. That’s because fresh human urine is sterile and so free from bacteria. Apparently, it’s only when it’s 24 hours old that it turns to amonia and you get that awful smell.

If I’ve allayed your fears, and you’re tempted to give urine a try, (I’m still not sure I am) remember to dilute it; it will be too strong to go straight on plants. Dilute urine with water at a ratio of 10 or 15:1

(Though if you want to gee-up your compost, you can pour it neat on to a compost heap it’s a brilliant compost activator.)

Lastly, don’t spray it on leaves – urine is always best applied directly to a plant’s root system. So put it on the soil.

Well that’s it from me. Seven different (in every sense of the word) plant food recipes for you to try. Happy, money-saving gardening – x