In short: A hanging basket fails for one reason far more than any other — it dries out. So plant it around water: a liner that holds the compost in, a mix built on coco coir (2 parts coir : 1 part peat-free compost : ½ part perlite, plus a slow-release feed), plants packed in tightly, planted from late April under cover and hung out once the frosts are over in late May or early June, then checked every day. A 35 cm basket takes about 10 litres of mix; one 5 kg coir brick does a dozen.
When to plant hanging baskets in the UK
The Royal Horticultural Society (RHS) timing: plant summer baskets from late April onwards, but keep them under cover — a greenhouse, porch or cold frame — because the tender bedding in them needs protection from frost until late May or early June. If you have nowhere frost-free, wait and plant once the risk has passed; garden centres sell plants right through May. Harden the baskets off for a week or so before they go out for good. Winter baskets are planted between September and November.
What you gain by planting early under cover is a basket that is already full and flowering when it goes up, rather than one that spends June filling out.
Liners: coco liner, moss or something else
A solid plastic or rattan basket needs no liner. A wire basket does — the RHS suggests ready-made cardboard or fibrous liners, or moss raked from your own lawn laid about 1.5 cm thick, and cautions against buying sphagnum moss unless it is from a sustainable source.
| Liner | Pros | Cons |
|---|---|---|
| Coco liner (moulded coconut fibre) | Neat, natural-looking, lasts two or three seasons, easy to cut planting slits in | Coir fibre holds very little water itself — it is the compost inside that matters; drains fast at the sides |
| Lawn moss | Free, holds water well, plants push through easily | Needs a thick even layer; dries and shrinks in hot spells |
| Cardboard / pressed-fibre liners | Cheap, tidy | One season; can slump when wet |
| Old wool jumper, hessian, felt | Reuse; wool holds water | Looks rustic; wool rots in a season |
A note on names, because it confuses people: the "coco liner" is made from the long fibre of the coconut husk. The coir we sell is the pith — the fine, spongy part that holds 8–10 times its own weight in water. Use the fibre to line the basket and the pith in the compost inside it. Whatever the liner, lay a saucer-sized circle of polythene (a piece of old compost bag) in the base before filling: it slows drainage from the bottom, where baskets lose most water.
What compost for hanging baskets?
The RHS's answer is that a good peat-free multi-purpose compost is fine for a one-season display, with some loam-based (John Innes type) compost added for anything long-term. The mix below starts from that and moves the balance toward water, because a basket hangs in the wind and sun with compost exposed on every side.
| Ingredient | Share | Why |
|---|---|---|
| Coco coir (expanded brick) | 2 parts | The water-holding ingredient basket composts add. Holds 8–10× its weight in water, stays open, re-wets in minutes if the basket does dry — a dried-out peat-based compost shrinks from the sides and sheds water. |
| Peat-free multi-purpose compost | 1 part | Nutrients and body. |
| Perlite | ½ part | Air at the roots and a lighter basket — a wet 35 cm basket is heavy on a bracket. |
| Controlled-release fertiliser granules | Pack rate, mixed through | Coir carries no food; a basket's compost is exhausted in about six weeks without it. |
Water-retaining gel granules are sold for baskets; with a coir-based mix you can usually leave them out — the coir is doing that job. If you do add them, use half the pack rate: too much gel and the basket stays sodden after rain.
How much mix, how many plants
| Basket | Mix | Coir in it | Plants (9 cm pots / plugs) |
|---|---|---|---|
| 30 cm (12 in) | ≈ 7 L | ≈ 4 L | 4–5 / up to 8 |
| 35 cm (14 in) | ≈ 10 L | ≈ 6 L | 5–7 / up to 12 |
| 40 cm (16 in) | ≈ 15 L | ≈ 8–9 L | 7–9 / up to 15 |
| One 5 kg brick (≈ 75 L) | ≈ 130 L of mix — about a dozen 35 cm baskets, or the baskets plus the summer patio pots. | ||
More plants than seems reasonable is the rule: a basket should look full the day it goes up. Plug plants bought in March and grown on in small pots are the economical way to get there.
How to plant a hanging basket, step by step
- Sit the basket in a bucket or a large pot so it stays level while you work.
- Line it (above) and lay the polythene circle in the base.
- Make the mix. Expand the coir brick in about 20 litres of water — how to expand a brick — then blend 2 : 1 : ½ with the compost and perlite and stir the fertiliser granules through at the pack rate. The mix should be moist enough to hold together when squeezed.
- Half-fill and plant the sides. Cut slits in a coco liner, or part the moss, at about a third of the way up. Wrap each trailing plant's rootball loosely in a strip of paper, push it through from the outside roots-first, then pull the paper away and firm mix around the roots. Three to five side plants for a 35 cm basket.
- Fill to 3 cm below the rim and plant the top: one upright plant in the centre, trailers around the edge leaning outward, fillers between. Firm gently.
- Water thoroughly — until it runs from the base — and let it drain.
- Grow it on under cover in good light, watering as needed, for four to six weeks. Pinch the tips of petunias, fuchsias and the like once to make them bush out.
- Harden off and hang after the last frost, on a bracket you can reach with a can, in sun for most bedding, and out of the worst of the wind.
Watering and feeding through the summer
The RHS aftercare advice is to check baskets every day in summer and water unless the compost is already moist; drying out becomes more of a risk as the plants grow and the weather stays warm or windy. The easiest check is to lift or nudge the basket — a light basket needs water. Try not to let it reach wilting point, and if it does, the RHS tip is to stand a bucket underneath so the water that runs straight through can be poured back. A coir-based mix makes that rescue work: it re-wets rather than repelling water.
Feeding: the granules mixed in at planting carry the basket for about six weeks. From then, a liquid feed once a week — general-purpose until the basket is full, then a high-potassium (tomato) feed to keep the flowers coming. Deadhead as you water.
What to plant
The RHS's list for summer baskets: Argyranthemum, creeping Jenny (Lysimachia nummularia), Dichondra 'Silver Falls', pelargoniums, trailing lobelia, petunias, salvias, Nicotiana, Glandularia (trailing verbena), Helichrysum petiolare and tumbling tomatoes. Edible baskets work well in the same mix — tumbling tomatoes (see coco coir for tomatoes), perpetual strawberries (best compost for strawberries), thyme, trailing nasturtiums and cut-and-come-again lettuce. For winter baskets: crocus and Iris reticulata bulbs planted among ivy, Gaultheria, heathers, pansies and violas.
Common problems
| Problem | Cause | Fix |
|---|---|---|
| Dries out in a day | Small basket, exposed spot, compost that has shrunk from the liner | Use 35 cm or larger; site out of wind; soak the whole basket in a bucket for an hour, then keep it moist — coir re-wets, dried peat-free compost does not |
| Flowers stop by August | Feed ran out; not deadheaded | Weekly high-potassium feed from six weeks; deadhead |
| Long, leggy plants with gaps | Not pinched; too little light under cover | Pinch tips early; brightest spot in the greenhouse |
| Yellow lower leaves | Hungry, or waterlogged | Feed; check the drainage holes are not blocked by the polythene circle |
| Basket blows about, plants bruised | Exposed bracket | Move to a sheltered wall; a heavier loam-based share in the mix steadies it |
| Bracket sagging | Weight of a wet 40 cm basket | Use a proper wall bracket with plugs; the perlite share keeps the mix lighter |
Frequently asked questions
What month do you put hanging baskets out?
Late May or early June in most of the UK, once the risk of frost has passed — later in the north and inland. Plant them from late April under cover so they are full when they go up.
What is the best compost for hanging baskets?
A moisture-holding, light, well-fed mix: 2 parts coco coir, 1 part peat-free compost, ½ part perlite, with controlled-release fertiliser mixed in. Peat-free multi-purpose alone works for a season but dries out faster.
Can you use peat-free compost for hanging baskets?
Yes — the RHS's own recommendation is peat-free multi-purpose. Adding coir gives it the water-holding that peat used to provide.
How often should you water hanging baskets?
Check daily in summer and water unless the compost is already moist — often that is every day in June, July and August, and twice a day in a heatwave for a small basket. Lift the basket to judge.
What fertiliser should I use in a hanging flower basket?
Controlled-release granules in the mix at planting, then a weekly liquid feed from about six weeks: general-purpose first, high-potassium (tomato feed) once the basket is in full flower.
How do you plant a hanging basket with a coco liner?
Fit the liner, put a polythene circle in the base, half-fill with mix, cut short slits through the liner for side plants, push them through roots-first, fill, plant the top, water well.
What can I use instead of a hanging basket liner?
Moss from your own lawn (the RHS suggestion), an old wool jumper or felt, hessian, or a solid-sided basket that needs no liner. Avoid bought sphagnum unless it is certified sustainable.
One washed, calcium-buffered 5 kg brick — about 75 litres of the water-holding ingredient, enough for a dozen baskets, delivered free across the UK.
Shop the 5 kg brick → Work out how many bricks