If you want your houseplants to stay healthy and happy, follow Glasgow PlantMama’s top 5 tips!

Do Not Over Water

The number one issue that plant parents seem to have is overwatering. People often think there is a direct correlation between the growth of a plant and the amount of water it is given, but this is not actually the case. Overwatering a houseplant can cause its roots to begin to rot, which makes it impossible for them to take on the water that they need to survive. This is why the symptoms of overwatering a plant can often look very similar to those associated with underwatering it.

Houseplants can tolerate underwatering far better than they can tolerate overwatering, and usually like to dry out in between waterings. This is especially true of plants with tubers or rhizomes (a modified stem beneath the soil that stores water and looks a bit like a potato), such as the Zz (Zamioculcas zamiifolia). I always recommend The Finger Test when deciding whether it is the right time to water, rather than going by a set schedule. Simply using your finger to feel the top 2-3 inches of your plant’s soil and decide whether it feels dry enough to require more water, or wet enough to be left for a little while longer. A good rule of thumb is to water the plant if the soil is dry and crumbly, and to leave the plant alone if the soil is moist and sticks to your finger.

Another good tip for making sure you do not overwater your houseplants is actually leaving them in the plastic nursery pots that they come in, then placing that pot inside the decorative pot that you would like to use. The nursery pots have drainage holes in the bottom that allow any excess water to run out of them and collect in the decorative pot or saucer that you have it sitting in. You can empty any excess water 30 minutes after watering.

In most cases (barring a few exceptions) tropical houseplants really only need to be watered once per week or so, while cacti and succulents on the other hand, require far less – once per month in the summer and not at all during the winter. It is also important to note that liquid fertilisers also add to the soil’s water content and should be used following the specific directions, in place of watering. For most tropical houseplants, I recommend watering one week then feeding the next week during the summer months.

Understand Your Plant’s Positioning Requirements

The prescribed light levels for various houseplants can sometimes be a bit confusing but it is important to understand their requirements if you want to keep your houseplants happy. Giving a plant too much direct sunlight or not enough sunlight can lead to scorching or wilting of the leaves and leave you with a rather unhealthy plant. I have defined the most common light conditions below and included examples of rooms or areas in your home that might fit these requirements.

Bright Direct Light

Bright direct light is the most sunlight that you could possibly give a plant. This is often reserved for palms or cacti, and is usually found in conservatories or windowsills that get the sun most of the day. Do be cautious of the plants that you put in these areas; succulents for example do like very bright light, but can get sunburnt in areas of really harsh, bright, direct sunlight.

Bright Indirect Light

Most plants actually prefer bright indirect sunlight. This can normally be found on a table that is near a window, or a bit further back into a room that receives a lot of sunlight throughout the day, such as a kitchen or living room. Bright filtered light could be on the windowsill of a frosted window or one with gauze curtains that filter some but not most of the sunlight.

Medium Light

Most of our homes here in Scotland have a fair amount of medium or filtered light. A bit further back into a bedroom, living room, or kitchen, medium light is an area of sunlight that is diffused through a room or gauze curtain. Some people also refer to this as dappled sunlight. Most plants that can tolerate low light will thrive in medium light.

Low Light

Low light is not the same as no light. While there are quite a few houseplants that can happily survive in lower light areas, such as a hallway or bathroom, there aren’t any houseplants that can tolerate absolutely no natural light. All plants need sunlight to photosynthesize, and while grow lights can definitely be helpful, some natural light is recommended to keep your plants as healthy as possible.

Know Your Medium Before Repotting

When repotting a houseplant, it is very important to understand the specific plant’s soil needs, as this can vary widely from plant to plant. While succulents and cacti prefer a mix that is very sandy and well draining, tropical plants often prefer a medium that holds a bit more water and nutrition for them. I always recommend doing a bit of research before repotting your plants, or asking the shop where you bought the plant. It is possible to buy specific soil mixes for cacti and succulents or tropical plants at most garden centres but for the avid houseplant owner, it is also very cost effective and easy to mix your own soil.

As a general rule, I  follow these two recipes:

• Tropical Plants: 40% coco coir, 30% perlite, 30% worm castings, a few handfuls of orchid bark (optional, for added drainage).
• Succulents and cacti (or plants that like very little water): 40% coco coir, 30% perlite, 20% mixed gravel or small stones, 10% coarse grit.

Types of Potting Medium

Coco Coir

This is a really eco friendly and sustainable organic matter made from the outer shell of a coconut. It is often available as a dehydrated brick. Simply follow the instructions on the package to rehydrate it and use it in your medium mix.

Perlite

This is a type of mineral that aids in the draining abilities of the soil mix.

Worm Castings

This is a type of organic matter produced by worms that contains an incredible amount of nutrients for your houseplants.

Orchid Bark

Often used for repotting orchids, this is a type of organic material that increases the drainage of the soil mix. This is optional if using perlite, but does help. 

Mixed Gravel/Small Stones

Small stones or mixed gravel help increase the drainage in soil mixes intended for desert plants such as succulents and cacti that require very little water and a very well draining medium.

Coarse Grit

Coarse grit or sand is another good way of increasing the drainage of a medium intended for a plant that needs very little water or is prone to root rot. 

Do Not Fear the Odd Yellow Leaf

When tending to houseplants, the odd yellow leaf is inevitable, and is not the end of the world! It does not mean that you have failed as a plant parent but rather that your plant is most likely letting the smaller, older leaf die back so that it can utilise all of its resources to continue to produce happy and healthy new growth. Nine times out of ten, a lower yellow leaf is an early sign that your plant is likely rootbound in its pot. A good way to check whether this is the case is to lift up the plant and see whether there are roots growing out of the drainage holes (another good reason to keep your plants in a nursery pot!). If this is the case, then it is time to repot! Research your plant and which potting medium is suitable, then repot the plant into a new nursery pot that is roughly 3-5cm larger in diameter than the previous pot.

If you only have one or maybe two small yellow leaves, then it can do more harm than good changing up the watering pattern or the plant’s positioning. Check whether it is time to repot the plant and if that doesn’t seem to be the case, keep an eye on the plant for a little while longer. There isn’t really cause for worry until two or three medium sized lower leaves start dying back or they feel very soft. If the soil is also wet, then these are signs of overwatering and potentially root rot. There is still time, though, to save the plant: it simply needs to be repotted into a dry medium and have its rotten root (if any) gently pruned back.

Pests Are Inevitable – Deal With Them Safely

Unfortunately, pests often come with the territory when bringing nature into your home, but there are some great ways to keep them at bay. I swear by neem oil for all manner of creepy crawlers. It works on every pest that I have ever come across and, if diluted properly, does not hurt the plant at all. It’s a great product to have on hand.

When using neem oil, mix about 10 drops in a litre of filtered water with a good squirt of fairy liquid, and shake it well. I then pour this solution into a spray bottle and spray down the plant’s foliage and the top of its soil. I also like to use this spray on any new moss pole or stick that I bring in to support my larger plants.

It is also a good idea to use the neem oil solution on the soil of your plants – I like to water them through with it like I would normally use water – this kills any gnat larvae that might be breeding in your plants soil. After watering them with the neem oil solution, it is important to let the soil dry out almost completely before the next watering.

If you have flying pests, such as gnats, then I recommend diffusing lavender oil. It is a wonderful way of keeping the gnats away and making your home smell lovely but it is important to be careful when using it around sensitive pets, as it can sometimes upset their respiratory systems. If this is a concern, then yellow sticky traps on a nearby window or on a post in the back of your plant pot are also very effective.

Emma Kelsey is the founder of Glasgow PlantMama, a houseplant business that offer houseplants and care tips. Follow Glasgow PlantMama on Instagram and Facebook.