Onion, Potato and Orange Peel Water for Plants: What Each Does
Onion peel water for plants, potato peel water and orange peel “fertilizer” are three different things, and only one of them carries much into the jug. Potato peel water picks up starch and a little potassium, onion peel water is mostly coloured water, and orange peel water carries peel oils but very little plant food. All three peels do far more for a pot when they’re chopped and composted or buried. If you do soak them, soak covered, use within 48 hours, dilute, and never pour stinking water on leaves you’re going to eat.
Quick facts
- Soak time: 24 to 48 hours, covered, then use the same day.
- Dilution: 1 part peel water to 1 part plain water.
- How often: once every week or two, in place of a normal watering.
- Better use of the peels: chop, then compost or bury 5 to 8 cm deep.
- Throw out: any peel water that smells rotten, is slimy, or has wrigglers in it.
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Why peel water is weaker than it looks
A peel keeps most of its nutrients locked inside its cells. Soaking for a day or two lets out only what dissolves easily: some potassium, sugars, a little starch and colour. The rest, including most of the calcium and nearly all the fibre that feeds soil life, stays in the soggy peel you strain off. So the water is a light feed, and the peel is where the value is.
There’s another thing going on in the jar. After about two days in warm weather, bacteria use up the oxygen, and the water starts to smell like a blocked drain. That smell means the mix has gone “anaerobic”, and pouring it on pots adds more bad smell than benefit.
Strain the water, but keep the peel. The peel is where most of the goodness is.
Onion, potato and orange peel for plants, compared
| Peel | What’s in it | What the soak water carries | Best use |
|---|---|---|---|
| Onion (pyaz ka chilka) | Dry fibre, a little potassium and calcium, pigment | Colour, very little else | Compost |
| Potato (aloo ke chilke) | Starch, potassium, moisture | Starch, some potassium | Compost or bury |
| Orange, kinnow, malta | Fibre, sugars, strong-smelling oils | Oils, some sugar | Chopped small, compost |
| Mixed vegetable peels | A bit of everything | A little of everything | Compost |
Onion peel water for plants
The papery outer skin of an onion is mostly dry fibre with some potassium, calcium and the coloured compounds that make the soaking water turn amber. That lovely colour is the main reason people think it’s strong. It isn’t. The popular claim that onion peel water makes roses bloom or money plant bushier has no good backing; any gain is small and comes mainly from the watering. Onion skins are slow to break down, but they compost fine when mixed with wetter scraps.
Potato peel water for plants
Potato peels are the most useful of the three to soak, because starch and some potassium leave the peel quickly. That makes the water similar to rice washing water: a mild feed. The same starch means it spoils fast, so dilute it and use it on day one or two. Money plant fans love this one; in soil it’s harmless, but a money plant in a water bottle should never get peel water or peels.
One genuine trap: potato peels can carry potato diseases such as blight and scab. Tomatoes, chillies and baingan are in the same plant family, so don’t bury peels from spotted or rotten potatoes in their pots. Send those to the bin. And peels with eyes can sprout; a surprise potato plant in your rose pot isn’t a disaster, but it competes for space.
Orange peel fertilizer for plants
Kinnow and orange peels are rich in sugars and in the fragrant oils you smell when you bend a peel. Those oils slow down rotting, so a whole peel can sit in a pot for weeks and grow blue-green mould on the way. The sugary white pith attracts ants. Chopped small and mixed into a compost bucket with dry leaves, citrus peel breaks down well enough.
What about pests? Some insects do seem to dislike citrus smell, but a few peels laid around a pot won’t protect a plant in any reliable way, and the sugar can bring more ants than it keeps away. Treat it as compost, not pest control.
How to make vegetable peel liquid fertilizer (if you want to)
- Collect a handful of peels (about 1 cup, loosely packed) from one day’s cooking. Wash them first if they came from unwashed vegetables.
- Chop into 2 to 3 cm pieces and put them in a jar or bottle with 1 litre of water.
- Cover with a lid or a cloth tied tight, so mosquitoes can’t reach the water.
- Keep it in shade for 24 to 48 hours. No longer.
- Strain. Mix 1 cup of the peel water with 1 cup of plain water.
- Pour it around the base of the plant, on the soil, not over the leaves. About 250 ml suits a medium pot.
- Bury or compost the strained peels the same day.
Use it once every week or two, in place of a normal watering. If the water smells rotten or looks slimy at any point, tip it into the drain or compost, not onto your pots. On herbs and leafy greens like pudina, dhania or palak, water the soil only, and wash what you pick.
Composting beats soaking for all three
Every peel in this article gives more when it rots slowly in soil. A bucket with alternating layers of peels and dry leaves or shredded cardboard turns into dark, crumbly compost in a few months, and that compost feeds a plant more evenly than any peel water can. If you have no space for a bucket, chop peels small and bury them 5 to 8 cm deep near the edge of a large pot, a different spot each month.
Many peels shouldn’t go to plants at all, because they’re good food first. Lauki peel, gobi stalks and mooli leaves all cook well; see edible peels, stems and leaves. And the banana peel for plants guide covers the scrap people ask about most.
Surprising facts
- Onion skins have been used for centuries to dye cloth and eggs in shades from gold to rust brown.
- The mist that sprays out when you bend an orange peel is mostly an oil called limonene, and it’s flammable enough to flare in a candle flame.
- A potato “eye” is a real bud. A peel strip that carries one can grow into a whole new plant.
Onion scraps and peels are toxic to dogs and cats, and green or sprouted potato peels are unsafe for animals to eat, so keep peel jars and compost buckets closed and out of their reach. Peel water left uncovered becomes a breeding spot for mosquitoes within days, so cover it, use it within 48 hours and never leave it in saucers. Wash peels from shop-bought produce, since pesticide can sit on the skin. Keep jars away from small children, and wash your hands after handling rotting peels or soil. For using citrus peel on skin, a different set of rules applies, including a sun-burn warning; see kinnow and orange peel uses.
More on turning kitchen leftovers into something useful is in the Zero-Waste Kitchen section. Kitchen and hair uses of onion, garlic and potato peels belong to another article; this one stays with plants.
Peel water for plants: questions people ask
Is onion peel water good for plants?
It’s harmless but weak. The water picks up colour and a trace of minerals, while most of the peel’s value stays in the peel, so composting the skins does more.
How do I use onion peel water for plants?
Soak a handful of skins in 1 litre of water, covered, for 24 to 48 hours, then strain and dilute 1 to 1. Pour about 250 ml on the soil of a medium pot every week or two.
Is potato peel water good for plants?
It’s a mild feed, a bit like rice washing water, because starch and some potassium come out quickly. Use it diluted and fresh, because it sours fast.
Is orange peel good for plants?
Chopped and composted, yes. Whole peels on the soil rot slowly, grow mould and draw ants, and orange peel water carries little plant food.
Which plants like onion peel water?
No plant has a special need for it. Roses, money plant and chillies all tolerate it as an occasional watering, but none of them will change much because of it.
Is potato peel good for money plant?
In a soil pot, a little diluted potato peel water or buried peel is fine. Never put peels or peel water into a money plant growing in a water bottle.
How long can I keep peel water?
Use it within 48 hours of starting the soak. After that it usually smells, and uncovered water can hold mosquito larvae.
Can I put vegetable peels directly in the pot?
Yes, as long as they’re chopped and buried 5 to 8 cm deep. On the surface they rot, smell and draw ants, flies and sometimes rats.
Do citrus peels keep insects away from plants?
Not reliably. A few insects dislike the smell, but the sugary peel can bring more ants than it keeps away.
Can I mix onion, potato and orange peels in one jar?
Yes, a mixed peel soak works the same way. Follow the same rules: covered, 24 to 48 hours, diluted, and used on soil rather than leaves.
Is onion peel safe around dogs and cats?
No. Onion in any form, including skins and scraps, can poison dogs and cats; keep peel jars closed and compost covered.