University of Vermont
Department of Plant and Soil Science
Winter News ArticleINDOOR WINTER GARDENING QUESTIONS
Dr. Leonard Perry, Horticulture Professor Emeritus
University of Vermont
How to treat unplanted spring-flowering bulbs, an amaryllis when
through flowering, and houseplants dropping leaves, are some of the
common indoor gardening questions this time of year. Many also
ask if there are food crops that you can grow indoors during winter.
If you purchased spring-flowering bulbs this fall, but didn’t get
them all planted, what should you do with them? Such bulbs really
can’t be held over until spring, or for another year, so go on and
plant them in pots. If you wait until spring to plant them outside,
or in pots, they will start growing with no roots, so won’t be
successful. Planting them now allows roots to form before they
start growing tops.
To grow roots, and receive the cold they need to flower, place
potted bulbs in a cool (40 degrees F or less) but non-freezing
location, ideally for 10 to 12 weeks. This could be an unheated
garage or basement. Or, you could place them outside in a protected
area, covered with plenty of bark mulch, straw, or soil. Then
remove when growth starts in spring.
If you got an amaryllis for the holidays, how should you treat it
once it has finished blooming? Once the flower stalk is finished,
leaves emerge. Keep the bulb watered and fertilized lightly through
the winter. This helps it build up reserves for next year’s bloom.
You can then place the potted bulb outdoors in summer, keeping it
watered if needed. Then in early fall bring it indoors, and
decrease watering over several weeks until stopped altogether.
Remove leaves as they die back, and let the bulb “rest” for about
eight weeks. Then resume watering.
If you had an amaryllis, and followed this process but got no bloom
this year, it may not have built up enough food reserves during the
year. If you just got leaves, keep the bulb watered and fertilized,
and hopefully this coming year it will bloom once again. Sometimes
after being “forced” they require a couple years before reblooming.
If you have a houseplant, such as a jade plant, and the leaves are
turning yellow and dropping off, what can you do? With a jade
plant, leaves dropping off is likely a sign that the soil is staying
too wet. As with most houseplants, too little water is better than
too much. If in doubt, don’t water, especially with “succulents”
such as the jade plant. Make sure the plant is not in a pot with no
drainage, nor sitting in a saucer of water. Using a clay pot, which
dries out faster than plastic, also is good for plants that don’t
need much water.
Make sure with houseplants that there is not a layer of gravel or
pebbles in the bottom of the pot. Some recommend this for drainage,
but in reality it only creates an area where water gathers and roots
rot, or decreases the amount of soil in the pot.
If you’re eager to grow some of your own food, or at least to see
something green this time of year, are there any crops you can grow
indoors? In addition to some herbs and sprouts, microgreens would
be a good choice. These simply are the immature greens of crops
such as lettuce and their relatives, leafy vegetables, and even some
edible flowers and buckwheat. Some catalogs sell special microgreen
mixes, often with various flavors and colors of leaves. Harvest
leaves when plants are only two inches tall, only two or three weeks
after they germinate. Grow in seed sowing mixes in shallow
containers. They need at least 4 hours of direct sun a day, as in a
south-facing windowsill, or you can grow them under plant grow-light
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