Can I grow food from kitchen scraps?

Which scraps genuinely regrow something worth eating, and which are an interesting science experiment and nothing more.

Difficulty: beginner
Time: 30 min
Read: 2 min

Short answer

Spring onions, lettuce bases, celery, herbs and garlic greens genuinely regrow and are worth doing. Avocado stones, carrot tops and pineapple tops grow into plants but almost never produce food.

Some scraps regrow the edible part directly and quickly. Others grow a plant that would need years and specific conditions to fruit. Distinguishing the two saves a lot of disappointed waiting.

What you'll need

Glasses or small pots
Water
Compost (optional)
A bright windowsill (optional)

Step by step

Regrow spring onions in water.Keep the root end with 3cm of white, stand it in a glass with the roots submerged. It regrows in about a week and repeats several times.
Regrow lettuce and celery bases.Stand the cut base in a shallow dish of water, changing it daily. New leaves come from the centre. Pot it into compost for a longer-lasting result.
Grow garlic greens from sprouting cloves.Plant sprouting cloves in compost. You will not get bulbs quickly, but the green shoots are mild and useful in cooking.
Root soft herbs from cuttings.Basil, mint and coriander from a supermarket packet root readily in water within a week or two. Then pot them up.
Grow potatoes from sprouting ones.This genuinely works. Plant a sprouted potato in a deep pot or bag of compost — it produces a real crop.
Regrow ginger from a piece with a bud.Plant shallowly in compost somewhere warm. Slow, but it does eventually produce usable rhizomes.
Be realistic about avocado, pineapple and citrus.They germinate readily and make attractive houseplants, but fruiting takes many years and specific conditions, and often never happens.
Do not bother with carrot and beetroot tops for roots.They regrow leaves, not roots — the root cannot regenerate. The leaves are edible, but you will not get another carrot.

Tips

Change the water daily for anything rooting in water. Stagnant water causes rot within a couple of days.
Water-regrown vegetables are usually smaller and weaker each time. Potting them into compost after the first regrowth gives much better results.
Supermarket herbs are several seedlings crammed into one pot. Splitting them into separate pots is more effective than any scrap-growing trick.

Common mistakes

Expecting an avocado stone to produce fruit — It grows a plant readily, but fruiting takes many years, needs specific conditions, and grafted varieties are what commercial fruit comes from.
Leaving scraps in the same water for a week — It goes stagnant and the base rots. Change it daily.
Expecting carrot tops to grow carrots — The root cannot regenerate. You get leaves, which are edible, but never another carrot.

Questions people ask

What vegetables can you regrow from scraps?

Spring onions, lettuce and celery bases, garlic greens, soft herb cuttings, and sprouting potatoes all genuinely work. Root vegetables regrow leaves only.

Will an avocado stone grow fruit?

It will grow into a plant readily, but fruiting takes many years, needs conditions most homes cannot provide, and often never happens. Treat it as a houseplant.