How often should I water my plants? By Lisa Price

How often should I water my plants?

This is one of the most commonly asked questions in store and online. There are few factors to consider when answering;

• The position of the plant in relation to the window or grow light. 

The closer to a window or grow light a plant is, the faster it will metabolise the water you give it, therefore you would water more frequently than a plant that is positioned more than a metre away from a window. 

• The structure of the potting mix the plant is in. 

If your plant is in a potting mix that is made up of just coco-coir for example, that will drain and dry out slower than a mix that contains chunks of say bark, pumice and perlite.

• The type of plant.

Cactus and succulent plants require their potting mix to dry out completely in between waterings. Zamioculcas zamiifolia has large rhizomes under the soil and a waxy leaf cuticle so can go longer periods without watering.

How much water should I give my plants?

I think it’s important to consider both of the above points when determining the volume of water to give your plant but if your potting mix is well draining and the plant is receiving adequate light, you need to water thoroughly. Giving your plant a thorough watering means pouring water over the top of the soil until it comes out of the holes in the bottom or sitting in a dish of water for about 30 minutes. If when you pour water on to the potting mix, it seems to run off and down the sides of the plant pot, it’s likely that the mix has become hydrophobic. In these circumstances, aerate the mix with a skewer or something similar. 

Should I top or bottom water? 

I’d say whatever works for your set up but it’s worth noting that if your plant is sitting in a pot cover, take it out before you water it as otherwise it will be sat in excess water. If your plant is particularly dense in foliage on the top - string of pearls, Fittonia or Peperomia, it’s best to water from below to prevent crown rot.   

Can I use tap water for my plants? 

Yep, in an ideal world you would use rainwater but tap water in the UK is fine. I’d suggest using tepid water rather than cold water as this could be a shock for the plant. If you grow plants that are sensitive to particular minerals - Calathea and Dionaea, we’re looking at you, use rainwater or distilled water. 

Should I water on a schedule?

No, each plant is different in its requirements, as mentioned their potting mixes may be different, some may be closer to the window or light source than others. The best time of day to water is in the morning, this gives the plant the longest opportunity of daylight hours to begin to metabolise the water, so they’re not sat in a wet potting mix for too long.

Do I need to water less in winter? 

Yes, plants typically enter a stage of dormancy or semi-dormancy during the darker months and since plants metabolise water based on how much adequate light they are receiving, watering frequency is reduced.