Winter Container Gardening

2017 December 6

In Alamosa, I move several plant containers indoors over the winter months.  I love seeing pink bougainvillea and a geranium or two in full bloom on a dark evening. Harvesting fresh basil, flat-leaf parsley, thyme, rosemary, and sage is a joy. And this year we have a couple of planters with mixed greens for salads. A bit of indoor gardening helps me keep sane during the dark and cold time of the year!

We have a small indoor greenhouse that is also a passive solar collector area with a black, three-foot high trombe wall at the back.  Temperatures during sunny winter days can soar into the 90’s and insulated warm window drapes keep the plants from freezing at night.

I have to be selective as many plants can’t tolerate the large temperature fluctuations. Bougainvillea and geranium do very well in these conditions. Summer petunias and snapdragons don’t fare well at all. In the past, I’ve had good luck with hibiscus, but this year and last I had an outbreak of mealy bugs that I couldn’t completely control so said goodbye to them and left them outdoors.

Before bringing any plants into the house, I quarantine them in our outside greenhouse.  More and more I try to use pesticides that are people friendly.  However, often they don’t seem to be as effective as harsher products.  Also, I wash the tops and especially the bottoms of leaves if I see any bugs or eggs.

For the first time ever I had an outbreak of either white flies or mealy bugs on a geranium. In the past, I’ve never had pest problems on geraniums – I thought they were invincible! Said goodbye to two geraniums I’ve had for several years as I couldn’t seem to eradicate the problem before it got too cold in the outdoor greenhouse. The local garden centers will be happy to see me next spring!

Herbs seem to do OK inside.   They get a lot of sun in our house, but parsley and basil wilt a bit on sunny afternoons so I try to harvest in the morning. For some reason, basil plants seem to develop white flies over time.  I know, I know, this doesn’t really make sense.  But whether I bring plants home from Trader Joe’s or grow them from seed, they end up with white flies.  When the flies start taking over, I make a big batch of pesto and let the plants go. If anyone has a good idea for ridding basil of white flies, please let me know (Marilyn@AlamosaFlowers.net).  It’s my favorite herb. I’ve also had good luck with digging clumps of sage, oregano, and chives from the garden in October and combining them in a pot for winter usage.

Rosemary tends to look sad after a long winter in the greenhouse; the heat does it in and I end up with some dead twigs. However, its vigor returns after returning outside in the spring. Right now my plant is on our enclosed back porch that is not heated and it is doing well. I think I’ll decorate it for Christmas! Sadly, while rosemary prefers cooler temperatures, it can’t tolerate our cold winters.  It’s listed as a USDA zone 6(lows ranging from -10 to 0) plant and Alamosa has a zone 3-4 (lows ranging from -40 to -30) rating.

For the salad greens, I filled containers with a mixture of new and old potting soil. Surprisingly, the hardiest plant is a volunteer nasturtium.  I’ve never had one in the winter and am interested to see how it does. A bright orange or yellow flower in a winter salad sounds great!

The Lifescape Colorado website has several recommendations for winter container gardening that include: 1) paying attention to each plant’s individual needs, 2) not over or under watering, and 3) making sure to provide adequate fertilizer (they say container plants need more fertilizer than those planted in the ground).

I check the soil in containers at least every other day and use drainable pots in saucers so I can monitor the watering. The plants are on stands with rollers so I can easily move them around to take best advantage of the sunshine.

Flowers always make people better, happier, and more helpful; they are sunshine, food and medicine for the soul.” Luther Burbank