First published in April 2019
We've all done it - picked up a pot of herbs in a local supermarket and brought them home to watch curl up and die.
Just to reassure you, you're not a lousy grower. It's what these pots are designed to do.
Overcrowded with young plants to look attractive, they are only expected to be kept for a week or two, to supply you with fresh leaves before being thrown away.
Herbs will always do best when grown outside. But with a bit of T.L.C., they can be grown indoors on a windowsill, albeit with a much shorter lifespan.
Picking a plant
Look for healthiest by taking them out of the plastic sleeve and having a quick check at the base of the stems. Avoid any with apparent signs of disease or grey mould.
If you are buying from a supermarket or hardware store, try to purchase plants as soon as possible after they've been delivered to the shop. These plants have come from ideal growing conditions in a nursery to a trolley on the shop floor. This is probably colder, darker and drier than the nursery and the shock will knock the plant back.
If possible, try and buy from a grower or plant nursery who will have taken the time to ensure plants have had adequate water, sunlight and warmth.
Having got your purchase home, I'd suggest potting on straight away. There could be as many as 20 seedlings in each pot, which will rapidly use up the nutrients in the compost and struggle to thrive.
Divide the seedlings into groups of three, shaking off most of the original growing medium, and replant into 15cm (6") pots using new free-draining compost. This will also help reduce the possibility of pest infection.
Water the new plants well to settle them into the new pot and help them recover from the transplant shock.
Depending on your windowsill, you might not have space for all those plants. Use the extra leaves up straight away and compost the remains, or maybe gift the spares to friends and family or offer on recycling sites.
- Light: Herbs like as much sun as possible, especially during the winter, so pick south-facing windows. If you want to invest in some tech, additional L.E.D. grow lights will help prevent them from getting too leggy as they stretch for the light. Modern L.E.Ds don't generate heat so can be much closer to the plant. Remember to turn the pot occasionally to promote even growth.
- Water: These plants don't like sitting in water, so only water when the compost feels dry. Tip the drip tray out after 20 minutes. Remember, as the roots fill up the pot the more frequently it will need to be watered. It's also worth placing the containers on a humidity tray full of gravel and water. The gravel holds the pots above the water and the evaporating water will help to maintain a balanced atmosphere.
- Warmth: Beware of frosts. Plants on windowsills can still be affected by the cold, especially after you've drawn the curtains. You might need to drop them into the room for the night. Conversely, on a bright summers day, the glass can intensify the heat, so soft new plants may need shading.
- Feed: Herbs grown without feed have a more intense flavour; however older plants that have filled their containers will benefit from some additional help. My personal preference is an organic seaweed feed, but there are plenty out there to choose from. I apply a quarter of the recommended dose once a week to pre-watered pots. Over fertilisation can lead to a build-up of nutrients, which does more harm than good.
- Pests: Herbs grown indoors are likely under stress and pests will make a beeline to them. Unfortunately, sometimes they arrive with the plants in the compost. My first action upon spotting bugs is to gently dunk the whole plant under tepid water (elbow test for the mums amongst us). This will hopefully wash off any pests without shocking the plant. If that doesn't work, careful inspection and culprit removal can also help. There are organic pest control sprays. However, because these are herbs we want to add to food, I'm very reluctant to spray anything.
If you do have space outdoors, then move the herbs out for the summer. After being slowly acclimatised to the UK weather, this will provide much better results.
For the apartment growers, don't be disheartened! If your herbs only survive a couple of months, that's four times longer then the shops expected. You're superstars. Have you thought about growing herbs from seed? This could be your next challenge, if you're ready to accept...