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INDOOR DECORATIVE PLANTS NEED EXTRA TLC DURING WINTER MONTHS:

Q:   I do not have a green thumb but I enjoy plants. I tend to 30 houseplants at our office. We have several peace lilies, pothos, philodendrons, spider plant, wandering jew, jade, lipstick plant, sago palm etc. they are all just ok.  Some have a little black winged bug so I have used insecticide soap but still have some yellow and brown leaves.  They just aren't at their best. I so much want to have strong beautiful green healthy plants. What do you recommend to use?  Foliar fertilization or soil or root feeding? Please help!

A:  What you're experiencing with your decorative plants is very normal in the winter.  Your office (or house) plants are probably not as their best for a couple of reasons, but my guess is that it's primarily due to the lesser light intensity of the winter sun.  Just about everywhere in the U.S. get's more sun than we do up here in the Michigan winters, but for almost everyone it's usually less than the plants are used to in the summer months.

LIGHTING: 

Is your office lit by fluorescent bulbs?  If so, you could replace the bulbs closest to the plants with new bulbs.  As fluorescent bulbs age, they decrease in intensity, not so much to our eyes, but as far as a plants lighting needs are concerned.  Replacement of these bulbs with new "cool white" tubes or bulbs makes a huge difference to the plants.  Expensive grow lights are nice, but regular cool white tubes are OK for plants for about 6 or 8 months when they're new (enough to get through the winter).

FERTILIZERS: 

As for the plants nutritive requirements, a common first impression is that giving them extra fertilizer might help, but when a plant slows down due to lack of light, they can't effectively use fertilizer at all.

One product that will help them though is "Superthrive", which goes a long way for a suffering plant.  Superthrive is inexpensive, and although it's not a fertilizer, it contains natural hormones (along with other non-fertilizer supplements) that will give them a nice little burst of energy.

Another less known secret would be to give the plants a very small taste of some natural sugars.  More specifically, I'd recommend using some "natural-unsulfured blackstrap molasses". You can safely use about 1/2 teaspoon in a gallon of watering for a one time treat for your plants.  The plants will use the sugar to store in their leaves for an energy source to help them through the stress period.  Normal table sugar is NOT a good alternative.  I'd stick to the molasses, or maybe about the same quantity of honey.  Don't overdo it!

INSECTS: 

The bugs you've got are probably thrips, and need a different treatment than insecticidal soap to be completely eliminated.

These particular insects are a growing problem for just about all indoor gardeners, but they seem to have become especially annoying in the office environment because they are attracted to the dim bluish light of computer monitors.  If you're seeing this attraction at all, then it's a confirmed case of thrips.  If not, they may be fungus gnats, and the treatment would still be the same, but not as necessary, because gnats won't hurt the plants as much as thrips will.

My recommendation for either of these insects would be a product called "Monterey Garden Spray".  It's a natural bacterial treatment that comes in a concentrate, and when mixed up and sprayed on the leaves and stems of the affected plants, it should stop them.

So, new bulbs, Superthrive, and Monterey Garden Spray and your plants will thank you.