…to bring the last of your houseplants indoors if they have been holidaying outside.
Here in the far south east of England the temperatures have dropped to about 3c overnight, which means that even the mediterranean-type plants (those hardy to just above or brief periods below 0c) will need protection.
If you are faced with squeezing the last of your plants into an overcrowded living environment you are not alone, this is what I have learned from years of trying.
Coming in from the cold
You will need to tidy up your plants before you bring them in – remove weed seedlings, dead`and damaged leaves and check under the pot. This is where the slugs and snails hide. If you have bare compost you can top with grit or gravel, this makes the plant easier to water and also discourages sciarid flies (often known as bin flies or compost gnats) that live around compost. Check to see how damp the compost is, so that you are able to bring them into synchrony with your watering routine. If it has rained recently and they are soaked through, you may not need to water for a couple of weeks, but this is very dependant on where you site them (sun/shade) and how warm your home is.
During the summer your plants will have become accustomed to a lot more light than they will receive in your home (unless they are to move into a conservatory or similar). They will also have grown a bit tougher and stronger through dealing with wind and rain. They will need good daylight, and also a period of adjustment to the change in conditions. Depending on the number of plants you have, you may need to prioritise the light levels; south and west facing windowsills for cacti and succulents, north facing for dark-leaved foliage plants etc. You will also need to find them saucers or pot-covers so that they don’t drip onto your surfaces.
Containers and pot-covers
In my experience the use of pot-covers and containers is the main reason that people overwater their plants. The plant can sit for weeks or months in a puddle of water without it being obvious until it is too late. If you know that you are an nurturer and overwater your plants, use attractive pots with drainage and either matching saucers or transparent plastic ones. Alternatively you can use a layer of 1cm or so of gravel at the bottom of your pot to give yourself a safety margin. Or get into the routine of emptying out your pot-covers an hour after each watering.
I never have enough space as I have a tendency to buy plants over the summer when I have a comparatively empty indoor space, and then quail in horror each autumn when I realise I have to house all of them. This is what I do to get past this problem.
You can expand your windowsill space using shelving (or if you are in a rental, a piece of driftwood balanced on pots). This enables you to make use of as much light as possible and gives you an attractive display.You will note that i am using a range of saucers and containers, partly because I err towards the neglectful, so I can get away with some undrained containers. There is a terracotta saucer being used in addition to the plastic tray for one pot, this because unglazed terracotta is porous and will damage surfaces that it sits upon; it will (as a friend can testify) turn carpet mouldy underneath and raise paint and varnish.
Put plants on top of other plants – if you have larger plants like this Ficus lyrata you will have a whole extra surface to keep things on. When you are doing it, bear in mind how much light will make it down to the understorey of your houseplant forest. As you can see by the graininess of this photo, it isn’t very light here, but Aspidistra ‘Milky Way’ is quite tolerant of low light levels.
Another example here, a Philodendron bipinnatifidum (in a cat bed that the cat disapproves of) supporting a Tradescantia and a Ledebouria. The philodendron spent the whole summer outside, and is stretching (etiolating) in the comparatively low light indoors, the leaves stay the same size but the stalks extend to get closer to the light.
You can also use mirrors (one here propped up on the floor with a spider plant) to reflect the light you have to make the most of it. If like me, you also have a lot of air plants, they are very happy pinned to chicken wire screens (mine is hung from the curtain hooks) over a window. And at the bottom, many of my cacti and succulents together, taking advantage of their similar cultural requirements to make my life easier.
I have not found supplementary lighting much use in a domestic environment for houseplants. The majority of lighting that is suitable for plants (in terms of wavelength, strength and heat transmission) has to be placed very close to them to be of any benefit, and therefore tends not to be either practical or aesthetically pleasing. However, with LEDs becoming much more common in these field I am hoping that eventually gains in this area will carry over from commercial and er.. underground horticulture to create something usable in the average home.
Remember to give your plants time to adjust, and keep an eye out for sneaky pests like tortrix moth caterpillar (see above on begonia), and sudden changes in growth habit (can be a sign of overwatering).