Winter is coming but before you get too upset there's still Autumn to enjoy! Autumn is an exciting season for indoor plant lovers as plants are using energy built up over the warmer months to have one last growth-spurt. While plants are in this phase of active growth it is important to start thinking about the months ahead.
There are many environmental changes your plants will have to adapt to:
Watering - In the cooler plants when plants aren't actively growing their water use is much less so it is important to decrease the frequency of watering. Plants are much more likely to survive drying out completely in the cooler months than they will being overwatered. When you water you should still make sure you have watered thoroughly but then wait until the potting mix has almost completely dried before watering again. Plants that are over watered suffer from a lack of oxygen which leads to the death of roots and the plant loses its vigour. Plants may suffer from stunted growth, yellow leaves and in worst cases blistering on leaves and water spots which damage your plants cosmetically. Worst case scenario the crown of the plant rots. Damaged roots also have little defence against pathogens in the soil.
Light - As the sun gets lower in the sky the amount of light your plants receive can change. North facing windows in particular may be the perfect spot for an indoor plant during summer when the sun is directly overhead but as we head into Autumn they can begin to receive more hours of direct sun. South facing windows that received a good amount of light through Summer will lose this light in Winter. Even in Winter a foliage plant can be burnt or blanched by an excess of direct sun. The opposite can also occur in spots where a plant was previously receiving a good amount of light as the sun may lower behind a neighbouring house or large tree. Being mindful of how light moves around your home means you can be proactive in assuring your plants are kept in their optimum positions.
Fertiliser - A good fertilising regime is great for keeping your plants happy and healthy. When plants are actively growing you can get pretty liberal with fertilising as long as you strictly follow correct dosages, By the middle of Summer every second watering is fine as the plants are actively growing and to that they need plenty of energy! As it cools down there are a couple of reasons why you should reduce the frequency of fertiliser. Firstly you want Summer growth to be properly hardened off before Winter. If you fertilise steadily into late Autumn you may be pushing lush new growth that will be soft and more likely to become damaged. Secondly, An excess of fertiliser in a pot can cause salts to build up as you aren't watering as frequently to flush them away.
Temperature - Be mindful of what the tolerances of your plants are. Some rooms may be bright and warm during the day but overnight cool off significantly. Some indoor plants such as Monstera or Kentia palms can tolerate quite low temperatures and will be quite happy in a cold room whereas others like many of the Peperomias and Calatheas will prefer temperatures to stay above 15 degrees. Plants will often tolerate temperatures outside their preferred range for long periods but it will slowly weaken them making them susceptible to pests and diseases. It is also important to take into consideration artificial heating as rooms or offices that stay heated are likely to need more frequent watering even in the cooler months. Never position your plants near heating ducts. As a general rule, The colder the room the more you should allow your plants to dry between waterings. Most indoor plants will tolerate cool conditions but not if they are wet and cold at the same time.
Autumn is the season to ready your plants for the months ahead. Observe your plants a little more closely. Are they receiving more or less light than previously? Are they taking longer to dry? By observing your plants now and making the relevant adjustments you can be sure to get them through Winter and powering into Spring!