October 2018

So, with the cooler temperatures, it is time for YOU to start planning your winter housing for the tender plants you wish to keep.

There are a few problems you need to consider:

  1. A house is usually a hostile environment for plants: dark, dry, and way too small!
  2. Outside there is an ongoing battle between prey and predator, even on the bug level.  In the house, there is little to no “good” bugs to eat the “bad” bugs.  For example: there are no lady bugs in the house to eat the aphids; so the aphid level in the house explodes.  The moral of the story: make sure what you bring inside is as clean of pests as possible before you bring them in!
  3. Outside you can and should water with abandon, allowing the soil to be leached often.  Inside, we put a saucer under the pot and don’t water too heavily (or else the carpet is ruined). This causes the salts in our hard water to accumulate in and on the soil.  This can burn the roots.  If your water is “softened”, don’t use that on your plants!  The salts in a water softener are sodium not calcium (found in hard water).  Sodium is toxic to plants – think sand dunes at the ocean!

So… What do you do?

  1. Start moving your plants to a shadier spot to acclimate them to the lower light in the house.  It is much easier on your plant to gradually lower the light levels than to wait until that first frosty night to move them in.
  2. Consider trimming your plants back to “shrink” them.  This will allow them to fit inside your home a little more easily.  If you trim them now, outside, the mess and sap won’t be all over your floors inside.  Trimming makes them bushier (prettier); the new growth is also used to the lower light levels in the house, an added bonus.  Pruning also reduces the insect population.
  3. An easier way to carry over some plants is to take cutting and start new plants.  This way the plant is “fresh” and small.  Start rooting the cuttings now to ensure you have plants to over winter before your plants freeze out.  [I’ll try to get Oscar to write more about this topic next week. Amy]
  4. Start looking closely at your plants for bug issues now.  It is easier to deal with it outside.  There are many control methods, from squishing the bad critters to chemical warfare.  Do the easy thing first: If your pest population is on the tips, like aphids usually are, trim off the tips (see point 2, above).  Some plants are prone to spider mites, such as Angel’s Trumpets.  When we bring in our Angel’s Trumpets, we strip ALL the leaves off and hose down the remaining trunk just before bringing inside; this greatly reduces the spider mite problem and the plants seem to love it!  Mealy bugs or scale on your plants?  We recommend throwing them away unless they are very sentimental!!!!  While these pests usually only move to in-contact plants, we have seen situations where cats rubbing on the plants spread the insects.  Mealy bugs/scale are VERY hard to control.  Check for caterpillars – chewed leaves is a good give-away.  Pick them off.  White fly can be controlled to some extent with Safer’s Soap.  (Pluck off leaves if you have an infestation!)
  5. Start backing off on the fertilizer now for most house plants.  As the days get shorter the plants need less fertilizer.  Fertilizer is a large part of salt build up on and in the soil.
  6. Some plants like poinsettias, mums, kalanchoes need short days to bloom.  That is, they will bloom after they are exposed to fall’s natural day length for a set period of time.  When you bring these plants into the house where lights are on, that messes up with their lighting and do not bloom.  Plants that need short days to bloom must be in a room that is dark once the sun sets.  BUT, they must be in the sunlight during the day!!!  You can’t leave these plants in the closet for weeks.  They will die!

Let’s address some issues:

  • Your favorite plant is huge – bigger than your house will allow!  Well, some big plants are easy to root.  Just take some small young stems of the plant and either root them in water or in moist potting soil (NOT garden dirt!)  By taking cuttings and rooting them you can have a fresh start and don’t have to haul in that behemoth that you have growing outside.  Some plants that root easily: coleus, wandering jew, airplane plants, vining philodendron, impatiens.  We prefer to root in moist potting soil, in a bright but shady location, using Rootone to aid root development.  If you root in water, make sure you change the water frequently.  With either method, the plant must have light!  Make sure you root your cuttings before the frost takes your pet plant!
  • Some plants go dormant!  Yay!  This really helps you!  Some examples:  Mandevillas, cannas, dahlias, fuchsias, Bonfire begonias.  Wait until the first frost burns back the foliage; then cut them back to ground level.  Most dormant plants can be dug up and stored in a cardboard box or paper bag in dry peat moss and then stored in an area above freezing ‘til next spring.  Some, like Mandevilla and fuchsias, are best left in the pot, not cut back, stored in a cold area that is well above freezing (40 degrees).  Water the potted plants about once a month just to keep them from drying out too much.  Bonfire begonias will “put themselves to sleep” – you think you killed them!  We keep them in their pots and store as above.  In the spring they sprout very robust shoots!  Surprisingly, Bougainvilleas (those heat lovers!) can also be held over winter in their pots this way.
  • Caladiums and elephant ears also go dormant, but require warmth for the winter.  They need to be kept above 50 degrees and require no light as dormant bulbs.  We grow our caladiums in pots in the summer.  When fall comes we quit watering them and allow the foliage to die down.  Then we remove the dry foliage and store the pots – dirt, bulb, and all – on shelves in a warm spot ‘til April.  In April we start watering them and give them light.  Out they go in May, already planted!  If you dig your bulbs, shake off the dirt and let them dry out in a warm, dark location.  Once dry, place the bulbs in a paper bag and store in a warm spot in your house – under the bed, under the kitchen sink.
  • Geraniums go dormant as well.  Some people keep their geraniums potted, in a bright, but cold location, sort of actively growing.  Some people dry the plants out and store in the attic, garage, or root cellar.  They look scruffy in the spring, but take off the old ugly leaves, get the plants in the warm light and they will sprout lovely new foliage.
  • Potted roses can be kept in a dormant state in their pots in a cold garage.  Good light is optional.  Water once a month to keep them from drying out too much.
  • Don’t be afraid to experiment with your plants.  Some plants are hard to root, but you might get enough to carry you through.  Some plants can be kept colder than you expect.  Spare, unheated bedrooms with light are great places to overwinter plants.  In general, the warmer the location the brighter the location must be to keep a plant actively growing.  Cooler temps allow for less light (but no caves please).

What not to take in:

  • Many plants COULD be kept from year to year, but are not worth the indoor space.  Some examples: sweet potato vine or dragon wing begonia.  These are readily available at a reasonable price, so why bother.
  • Some plants are easy outside, but inside develop bad habits – Boston ferns shed and Diamond Frost euphorbia drops its leaves and blooms.
  • Some just make poor house plants.  For example, many hardy perennials need a cold dormancy (Hostas).  Others remain green year ‘round but still need a cold winter – with high light!  Examples are Hens and Chicks and Hellebores.  If they are comfortable, you will NOT be!  These plants love a cold greenhouse though, which is how we overwinter them.  (But of course, they can remain in the ground outside without a problem.)

So… start thinking about what you have room to keep.  What do you have the energy to keep?  What will your spouse/kids let you keep?  What is best to just replace next year?

From Hill Top Farms newletter, Sept. 2018