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The inch rule packs baskets for the full-globe look: a 14" basket takes ~12-14 plugs (sides and top). One trailing thriller-filler-spiller mix beats a dozen of the same. Baskets dry out DAILY in summer: the gel crystals and a dunk-watering routine (or drip line) keep them alive through a week away. Hang after the last frost, mid-May most of the UK.
What The Hanging Basket Calculator Works Out
- Plants per basket: the trade's inch rule, one plug plant per inch of basket diameter, so the common 14 inch (35cm) basket takes about 14 plugs threaded through the sides and crowded across the top. Generosity is the entire aesthetic: the goal is a globe of flower with no visible basket by July.
- Total plants: plants per basket x number of baskets, with a tray size rounded to sixes so there are spares for duds. The March mail-order tray of plugs is a fraction of the price of May's grown baskets.
- Compost: a rough volume from the diameter cubed (a 35cm basket holds about 10 litres), multiplied by the number of baskets, with the gel and feed noted because the assembly recipe is non-negotiable.
- Custom diameter and planting density (advanced): type an odd basket size and ease the inch rule for vigorous surfinias or million bells, which fill a basket at one plant per two inches where lobelia and bacopa want the full count.
- Plant cost (advanced): plugs x your price, and the cost per basket. Mail-order plugs run 40p to GBP 1 each in March; a ready-planted 14 inch basket in May is GBP 25 to GBP 45, which is the factor that funds the compost.
- Compost bags (advanced): bags at your chosen size and price, and the litres left over for pots and top-ups.
- Gel and feed (advanced): water-retaining crystals at about 2g per litre and slow-release fertiliser at about 4g per litre, mixed through the dry compost, with the tubs to buy. From July, weekly liquid tomato feed takes over as the pellets fade.
- Water and weight (advanced): a summer basket in sun transpires about a litre a day per 10 litres of compost, so the card gives the weekly watering for all your baskets. A watered 14 inch basket weighs 8-10kg: the bracket fixing goes into masonry or stud, never render and hope.
- Size table (advanced): plants, compost, watered weight and totals for 25cm to 50cm baskets. Hang after the last frost (mid-May for most of Britain), and rescue a crisped basket by full immersion in a bucket until the bubbles stop.