Despite our mild winter, our outdoor landscape is still dull and dreary. But our indoor landscapes are beginning to perk up. Houseplants that have been coasting through winter are reawakening, responding to lengthening daylight by sending out new leaves and, in some cases, even flowering.

Capitalize on those improved growing conditions by taking the time to get your houseplants in shape. It's a great way to get your hands dirty before the ground thaws. And, admit it, once you can be out in the garden, your houseplants will be left to fend for themselves.

Hungry for spring

Longer, sunnier days activate healthy new growth in houseplants. The additional energy produced through photosynthesis stimulates new growth, which in turn creates the need for supplementary nutrients.

That's why it's important to resume feeding in late winter. About once a month, with fertilizer designed specifically for houseplants, should do. Unless you're using an organic fertilizer that breaks down slowly in the soil, mix the solution at half its label-recommended strength to avoid burning the roots.

And don't apply fertilizer to bone-dry soil. Water first, then fertilize the soil a day or two later, while the soil is still damp.

Time to repot

Increased light also makes houseplants more resilient and able to withstand repotting.

Sometimes it's obvious that a plant is too small for its container. Here's how to check if it's not so obvious: Run a knife around the inside walls of the plastic pot, whack the pot on a hard surface, pop the plant out and examine the root ball. If you see a mat of roots encircling the soil in the shape of the pot, the plant needs to be repotted. If you see mostly soil, with a few roots running here and there, it doesn't (Just replace the plant in the container. No harm done.)

How to repot

Choose a container that's about an inch larger than the container the plant has outgrown. Make sure it has at least one drain hole so water is never trapped in the soil, which creates conditions that favor root rot. Cover the drain hole (or holes) with something that keeps the soil in, but allows water to exit freely, such as a piece of broken clay pot, a metal screen, an irregularly shaped stone or paper toweling.

Fill the bottom of the pot with enough fresh potting soil so that the plant sits at the same depth it was in its previous pot. Loosen the outer roots or take a sharp knife and make several shallow vertical cuts along the sides of the rootball to encourage new root growth. Put the plant in the pot and fill around it with soil.

After repotting, water thoroughly, then set the plant in a well-lit place that's out of direct sunlight. After a day or two, you can return the plant to its original location.

Give 'em the once over

Houseplants benefit from a good spring cleaning. Begin by checking each plant carefully for yellow or brown leaves that might be hiding beneath layers of greener, healthy foliage. Nip them off. They're unsightly and they can provide habitat for mites and insect pests.

It's also a good idea to trim back weak stems with smaller-than-normal leaves. New growth that develops under the improved light conditions of spring will be more robust and attractive. (Don't trim palms, though. They grow only from the uppermost point on each stem.)

All indoor plants accumulate a coating of dust over the winter months. (Homes with forced-air heat are typically dustier than others.) It's most obvious on plants with large, shiny leaves, such as rubber trees, but even the laciest fern with tiny fronds will look better with clean foliage.

To clean your plants, wipe off the top and undersides of each leaf with a soft, wet cloth. Use barely lukewarm water with a few drops of dishwashing liquid, just enough to make the water feel slippery.

If the plant has lots of small leaves, cover the soil with tin foil, tip the plant upside down and swish it through lukewarm water in a sink or laundry tub.

Let plants dry out of direct sun, then move them back soon, so they can continue to reap the benefits of the additional light.

Deb Brown is a garden writer and former extension horticulturist with the University of Minnesota.