(Not So) Green Thumb

Posted in 13 Nov 2018

Need a hand keeping even the hardiest cactus alive? If you manage to kill the un-killable, our group horticulture manager David Tetstall can help. Some people love nothing more than collecting soil under their fingernails every weekend. Others are a little more laissez-faire when it comes to their gardening practice. And while you can’t just chuck something pretty in a pot and hope for the best, Merivale’s David Tetstall explains how to keep a few choice indoor plants, cactus and herbs alive with minimal effort.


Most of your common indoor plants are tropical or sub-tropical understory plants (meaning they grow below the canopy), which is why they can live and grow in low light conditions.

David says you’ll still need to consider how much light they’ll be getting though, as the further away from a natural light source, the harder it will be for your plant to thrive. “If an indoor plant isn’t doing too well, try moving it closer to a window or door that lets in a fair amount of natural light.”

Don’t get too excited about the sun though! “You never want to put a plant that’s been in the shade for a long time in direct sunlight, even if it is something that can grow in full sun. Putting it straight into the sun will cause it to burn, just like you would.” Noted.

Heating and air-conditioning are not ideal for plants as they remove the moisture from the atmosphere, but obviously that’s not always something that can be helped. “Misting with a water sprayer regularly makes a big difference to the humidity level immediately around your plant– just spray directly onto the leaves – and make sure you give them a good clean with a damp cloth to get rid of built-up dust too.”

David says the biggest hurdle with indoor plants is figuring out how often to water them. “Overwatering is the biggest killer of indoor plants.”

To combat this, he recommends a simple finger test. “When I water indoor plants, I’ll first stick my finger into the soil up to the second knuckle, and if I feel any moisture in the soil, I won’t water the plant. Only once the soil feels dry do you give them a good soak. I’ll also use a weak liquid fertiliser once every two weeks, sprayed directly onto the foliage, to ensure they’re kept extra happy.”


Grren Thumb

1. Fiddle Leaf Fig “The supermodel of the indoor plant world! They need a little bit more light than the lily, so you’ll want to put them closer to windows or doors.”

2. Peace Lily “If you forget to water it, it will collapse quite noticeably. But once you give it a good soak, it will stand back up again – and won’t hold your neglect against you!”

3. Rattlesnake Plant “I love these for their colourful foliage. Water regularly in small amounts so they’re kept moist but never sitting in excess water.”


Contrary to popular belief, you can kill a cactus.

“Yes, you can,” laughs David. “But they’re fairly resilient so they’ll put up a decent fight.”

Succulents, too, are moderately forgiving, however a lot of succulents prefer semi shade and if you place them in full sun you’ll risk burning them. “Most cactus prefer full sun.”

When it comes to watering, less is more. “You don’t want to water them much, or at all, when they’re dormant – i.e. not growing in the colder months. If they’re sitting in wet soil, you’ll find they will rot.”

As it warms up though, you can water sparingly, and even give them a little fertiliser if you’re so inclined. “I love echeverias for their compact rosette form, and a favourite at the moment is Variegated Jade for its white and green striped fleshy leaves.


You don’t need a full-sized veggie patch to grow a few herbs that will add an extra pop to your meals… or cocktails! A sunny windowsill or balcony that gets at least six hours of natural light a day will do the trick.

“Plant your herbs using a good quality potting mix – one that’s free draining but with some water-holding capacity – and place a saucer beneath. This will help prevent the soil drying out during the day by retaining some of the excess water from watering.”

In spring and summer you’ll want to water them everyday, and David suggests pinching the tips regularly so they’ll maintain a compact form. “If you pinch out the tips, they’ll send out lateral shoots and stay compact.”

As for some hardy herb suggestions? “Mint, basil and parsley are all pretty sturdy. Taste great too!”