How To Use Horse Manure In Your Garden

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No good gardener ever turns down the offer of a load of well-composted horse manure. Some may even go weak at the knees at the very mention of muck. Why? Because horse manure is a fantastic natural fertiliser, soil conditioner and promoter of earthworms. For leafy plants, always hungry for nitrogen, there really is nothing better than a decent pile of poo. Nitrogen is quickly leached from the soil during the winter months, so an annual application of manure provides the perfect organic top-up. Flowering and fruiting plants also require potassium and phosphorus and although horse manure contains less of these elements, they are not so easily lost from the soil. Both can be supplemented using blood, fish and bone, which I apply liberally to our allotment at least twice a year. Now you know why our dahlias and sunflowers look so happy!

The big challenge with horse manure is getting hold of it. Chances are, if you live in the countryside, you already have a trusted source. If not, ask around and someone will be willing to share their dirty secret with you. Once located, you’ve got the challenge of getting it home and on to your garden. Horse manure is, by its very nature, bulky and you need a fair amount of it to make a difference. It can also be heavy, especially when wet. If you can get it delivered, do so, and take as much as you can deal with. A tonne of manure does not go as far as you might imagine. If you have any left over, it can be left in a corner to continue rotting down until you are ready to use it, or there will always be friends eager to take if off your hands. Be sure to know where your horse manure has come from and how it’s been stored, as occasionally it can be contaminated with weedkillers, the roots of perennial weeds or weed seeds. Do not be concerned about the appearance of straw, wood shavings or sawdust. Much of the value of manure is in the urine-soaked animal bedding, which is particularly high in nitrogen. However, if it’s still very loose and yellow, your manure has not rotted sufficiently. Until the natural matter breaks down properly, nitrogen will be ‘robbed’ from the soil, which is the opposite of what you want. As ever in gardening, patience is a virtue.

We are fortunate, because every January our friend drives down from North Kent with a horse box full of ‘black gold’. This magnificent stuff has been rotting down for five or six years, by which time it’s scentless, crumbly and the colour of a decent chocolate brownie. Each shovel-full is positively writhing with small red worms. Age is important, because fresh horse manure can be so high in ammonia that it will damage the leaves and roots of your plants. At this stage it will be smelly too. Some sources suggest it’s fine to use horse manure on the garden after three to six months, but at this age it could still be fairly coarse, caustic and bulky. After a few years it will have started to compost nicely, and whilst some of the nutrient levels may have diminished, the texture of the manure will be greatly improved. After five or six years, there is very little sign of straw and the manure is a beautiful, friable consistency.

Once you’ve got hold of your manure, you have a choice of what to do with. Spread over beds and borders, or beneath trees in autumn the earthworms will have done much of the work for you by spring. If applied over winter or in early spring, it might help to fork manure in lightly to distribute it evenly through the upper layer of the soil. I tend to be lazy and leave this until I am ready to plant the bed and then the manure can be turned in at the same time as planting. If sowing seeds, it’s wise not to sow directly on to a manure mulch as it will be too rich and too lumpy for successful germination. If you do want to dig your manure in, then add it to the bottom of trenches as you work. Adding manure to soil is a brilliant way of improving its water retention. Crops like sweetcorn, Brussels sprouts, kale and runner beans will reward you for adding generous helpings on a regular basis. As for how much to manure to apply, you can’t really overdo manure as you could chemical fertilisers. As long as it’s not cascading over the top of your raised beds it’s fine and will soon settle down once the worms get to work. Where you don’t want to apply manure is any place you’re hoping to establish wild flowers. Manure will make the soil too rich, encouraging competing coarse grasses and perennial weeds to take over.

Other animal manures are available, from cows, pigs and poultry for example, but rarely are these used alone or in quantity because they are very concentrated. Horse manure is much the best general fertiliser because it’s rich in organic matter and much more mellow. Spent mushroom compost is a good structure improver, but not that useful for adding nutrients to the soil. It also tends to be alkaline, so should not be applied to already alkaline (chalky or limey) soils like ours here in Thanet.

Any time between now and March is fine to add horse manure to your beds and borders provided it’s well rotted, if it’s fresher, you should apply it in autumn and let the winter weather take some of the raw strength out of it before planting. Poor, light, dry soils tend to benefit the most from any kind of organic matter, as it helps to add weight and conserve moisture. Soil where manure is applied annually for three years is said to contain ten times the number of earthworms and that’s certainly noticeable on our allotment.

Although there is some best practice when using horse manure on your garden, the main thing is to get on and add it. Provided it’s not fresh out of the horse’s derrière, you cannot go too far wrong. TFG.

Categories: compost, Fruit and Veg, Our Allotment, Practical Advice

Posted by The Frustrated Gardener

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19 comments On "How To Use Horse Manure In Your Garden"

  1. You lucky thing, you! My neighbouring farmer has retired and the dairy cows are gone from the fields around us. We used have all the manure we wanted and he was happy that we would come and clean out his calf houses every year. When we came here first, before we planted anything, I was able to add a foot of manure to the beds – brown gold, indeed!

  2. A trusted source is invaluable . Just like art & fine wine , provenance is everything. Some horse owners treat their paddocks with a long acting weed killer which can persists in the manure from the horses, despite composting it ,for up to 3 years . The risk is then to any plants which come in to contact with it. Manure from animals that have grazed on Grazon-treated areas is not suitable for compost , so do ask the question first .

  3. One drawback with horse manure is that horsed don’t digest hay seeds. If the maunure is not well rotted, you’ll get a fine crop of grass in your beds.

  4. Gads! We need to relocate it on Mondays, Wednesdays and Fridays, and it is not composted. At least it is a quick process. We get it fresh from the source to put onto the compost pile. Somehow, it all gets used. It helps that neighbors take a good volume of it.

  5. Sounds lovely! Horse and leaf manure and mushroom anything. Speaking of manure, Watch this old movie 🙂 you guys will love it; “Quackser Fortune has a Cousin in the Bronx”, starring Gene Wilder.
    XOX, Sandy across the pond

  6. Not sure if mushroom compost is as good but I have 7 farms around me and they can’t get rid of the stuff fast enough.

    1. It’s different. Not particularly nutrient rich but good for adding organic matter to the soil, which worms enjoy, and improving the structure. You should just avoid using it if your soil is alkaline – you would probably know if it was. Mushroom compost is also alkaline so the combination isn’t ideal for a balanced soil PH.

  7. Any idea what horticultural qualities pygmy rabbit poo in wood shavings has? Asking for a friend…

    Seriously, as we’ve added two pets to the family last spring, I’ve started to make use of their litter (is that the correct word here?) by adding it to beds and borders, usually as mulch, because it seems such a waste to throw it in the bin. There’s just one problem: we live in rented accomodation and the caretaker of the property isn’t best pleased with this. I’ve tried to convince him that it isn’t much different from the bark mulch he used to spread around the shrubs before, but have to admit that’s not entirely true. For one thing, the wood shavings are much lighter visually which make the mass of dark, pea-sized rabbit poo stand out so much better… The latter also does not dissolve nearly as fast as I had imagined. As it is a property shared with other tenants, I can’t have a big compost place to add it to instead either. So, if anyone has any experience using this potent mixture I’d be glad to hear about it, not least in order to confidently stand my ground 😄.

    1. What a tale! Give the rabbits are herbivores there is little chance of there being anything unpleasant in your mixture of bedding and poo. The best place for it is on the garden. If you composted it, you’d need some ‘wet’ material to go in between layers of woodshavings otherwise it won’t rot down …. And nothing will happen fast in the winter months as it’s too cold. Do you have the ability to dig it in at all, as that might speed up decomposition and make it less obvious to other residents? Dan

  8. Dan, do you have a huge Canada goose population? I don’t even think they migrate, I think they’re here all year long. It seems to me their poop might be good garden manure.

  9. Hello, great piece on horse manure, I.have friend near my allotment and he.keeps pigs, whats pro,s and cons of pig manure ? Thanks in advance.

    1. Hi Paul. Pig manure is rich and a good fertiliser. However, because pigs eat all sort of foods, it can carry dangerous pathogens like Salmonella and E. Coli so it must be very thoroughly composted and it’s best to avoid using it on food crops, just in case. Dan

  10. I have just collected bags of my usual pony manure, which I spread on flower beds.
    Its not very old and can see leaves in it that are not yet rotted.
    I am concerned to see, in the bags, billions of minute tiny white maggots.what are they ? are they harmful, what to do?

    1. Hi Ruth. It’s hard to be 100% certain without seeing it, but my guess is that the small maggots or worms are busy breaking down the organic matter for you and are nothing to worry about.

      If there are leaves in the manure that have not yet rotted then this could be a sign it’s not sufficiently mature and could be rather acidic. My advice would be either to put it in a compost bin for a few months to let it rot down and spread in the autumn, or to spread on a small area planted with reasonably tough plants to see how they fare before using the lot. Dan

  11. I’m getting a load of horse manure to add to our soil we flipped over this year for a bigger garden next year. We have poor soil and was going alto sprinkle it in the rows between what I have planted this year and til it in. My thought is, it will help the soil and the vegetables I have already without putting directly around each plant and risk killing them but can still get some nutrients from it. Is this a current thought?

    1. Hi Lisa. It depends how old / well-rotted the manure is. If it’s mature, then go for it. Watering well will also help and encourage worms to come and help mix it in. If it’s ‘raw’, you’re best leaving it to one side and waiting for winter. Dan

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