The What For If you love our Indoor Plant Food to get your plants growing and thriving, now level up with our 500ml glass refill bottle. Designed by us, proud-plant nerds, our liquid Indoor Plant Food is a special formulation of nitrogen, phosphorous and potassium (N.P.K), trace elements and seaweed as a superfood your plants will drink up. It's almost completely odourless and comes with its own marked dropper for exact measurements and minimal waste. Just one bottle will make up to 100L of plant fertiliser. Simply add the concentrate to your watering can at 1ml/litre, and water your plants as usual. No need to add any extra steps to your plant care routine - just add once and water in.