Why Late Winter Is the Best Time to Act

By the time February rolls around, most houseplants have spent four months surviving rather than growing. Central heating has dried the air, daylight has been weak and brief, and many of us have watered out of habit rather than need. The result is a plant that looks tired: yellowing lower leaves, brown tips, leggy stems and compost that never quite dries out.

This is a good moment to intervene, because the days are stretching and light levels are climbing. Growth you encourage now has something to fuel it. Wait until May and you have wasted weeks of the best growing window of the year.

Check the Roots Before You Do Anything Else

Leaves tell you something is wrong; roots tell you why. Before you cut anything back or reach for the feed, slide the plant out of its pot. Squeeze the sides first, then tip it gently upside down with a hand supporting the compost.

Healthy roots are firm and pale — cream, white or light tan — and they smell of nothing much. What you are looking for:

• Brown, mushy roots that fall apart in your fingers, with a sour or decaying smell. This is root rot, almost always caused by overwatering in low light.
• Roots circling tightly around the edge of the pot, or a solid mat with little compost left. The plant is pot-bound and needs a bigger home.
• Dry, brittle roots that snap rather than bend. The plant has been underwatered, or the compost has become water-repellent.

For rot, cut away every mushy root with clean, sharp scissors, keeping only firm tissue. Repot into fresh, free-draining compost and hold off watering for four or five days so the cut ends can callus over. If the roots look healthy, put the plant straight back and move on.

Remove Damaged Leaves — But Not Too Many

A yellow or crispy leaf will not turn green again. It is drawing on the plant's reserves for nothing, and it may be harbouring pests or disease. Take it off.

Be sensible about how much you remove, though. Leaves are the plant's solar panels, and a struggling plant needs every working one it has. Strip only what is genuinely dead or more than half damaged. On a plant with just six leaves, removing four leaves the plant with nothing to photosynthesise.

• Cut brown tips off spider plants and calatheas at an angle, following the natural line of the leaf, rather than snipping straight across.
• Remove spent flower stems at the base, not halfway up, so you do not leave a stump that dies back.
• Wipe your blades with soapy water or rubbing alcohol between plants, particularly if you have had any pest problems.
• Pull off crisp leaves with a gentle sideways tug if they come away cleanly at the stem — it is kinder than cutting into healthy tissue.

Increase Light Gradually, Not All at Once

The temptation is to move a pale, leggy plant straight onto the sunniest windowsill in the house. Do not. A plant that has adapted to low light for months has thin, tender foliage that scorches and bleaches in strong March sun.

Move it closer to the window in stages, over two or three weeks. Give it a south-facing spot for two hours a day to begin with, then four, and build up. Turn the pot a quarter turn each week so growth stays even rather than leaning permanently towards the glass.

The cheap wins matter as much as position. Clean your windows inside and out. Move anything blocking the light — a deep windowsill of clutter, a heavy curtain, a book stack. Dust is a genuine problem too: a grimy film on a large leaf can noticeably reduce the light reaching the leaf's surface, so wipe both sides with a damp cloth.

Ease Off the Water and Hold the Feed

A plant with damaged roots cannot take up much water, so watering on your usual schedule will finish it off. Push a finger two or three centimetres into the compost, or use a wooden skewer like a cake tester. Water only when it comes out dry.

When you do water, do it thoroughly until it runs out of the drainage holes, then empty the saucer after twenty minutes. Little and often leaves the lower compost permanently wet and the upper layer bone dry. Use water at room temperature, and let a filled can stand overnight if your tap water is hard.

Do not feed a struggling plant. Fertiliser salts build up in compost that is not being used, and can burn what few roots remain. Wait for clear signs of new growth — a leaf unfurling, a new shoot at the base — then feed at half the recommended strength, once a fortnight.

A Simple Spring Reset

Once a plant is stable, give it a proper refresh. Early spring is the right time to repot, since the plant has energy to recover. Go up just one pot size — roughly 2–3cm wider — because a plant in an oversized pot sits in wet compost it cannot use. Loosen the root ball and tease out circling roots with your fingers before settling it into fresh, free-draining mix.

For anything staying in its pot, top-dress instead: scrape off the top two or three centimetres of tired compost and replace it with fresh. It takes five minutes and makes a visible difference.

Finally, check every plant while you have it in your hands. Look under the leaves and along the stems for sticky residue, fine webbing, little brown bumps or white cottony patches. Fungus gnats hovering around the compost are a sign it is staying too wet. Deal with pests now, while numbers are low, and your plants will hit the summer in far better shape.