Never Fertilize Plants in December – Unless They’re One of These Rare Exceptions

Winter sends most plants into a quiet rest, with growth grinding to a halt as light fades and cold sets in. But you still may be asking the question, “Can I fertilize in December?” Usually it's a bad idea to fertilize in the winter – excess nutrients force weak shoots that succumb to frost or disease. Yet a handful of indoor bloomers and fruits keep pushing through the month and actually benefit from a careful dose of fertilizer at the end of the year.

You can fertilize plants in December only if they're actively growing indoors or currently blooming. Outdoor plants rest deeply in December, but houseplants under lights keep going. The same basics of fertilizer types and timing that fit any season apply here, too. Stick to diluted formulas to avoid fertilizer burn on these winter workers.

December fertilizing risks outweigh benefits for dormant plants, but the right ones thrive with it. December fertilizer should always be half-strength or less, mixed with lukewarm water. The key is watching for signs like new leaves or buds – that's your cue to feed sparingly. Let's take a look at the 10 plants that benefit from fertilizing in December.

1. Indoor Citrus Trees

Indoor citrus trees, like lemons and oranges, often bear fruit in winter if conditions stay warm. They need steady nutrients to support that load without stalling. Feed every 4-6 weeks with a citrus fertilizer diluted to half strength. The leaves will stay glossy and the fruit will develop nicely when you get it right.

Watch for yellowing leaves – that's a sign of deficiency. A balanced fertilizer like this citrus food from Amazon keeps pH low and iron available to plants. Water thoroughly after fertilizing to flush out excess salts. The pot should feel heavier, but drain fast. New growth will appear within weeks.

2. Potted Herbs

Indoor herbs like basil, rosemary, and mint push out leaves year-round when placed under grow lights. December fertilizing keeps them bushy and flavorful without a break. Use a light organic fertilizer every 3-4 weeks, mixed weakly to avoid leggy stems. The herbs will perk up, filling the kitchen with scent.

Pinch herbs regularly to encourage branching. An all-purpose liquid fertilizer like this from Amazon dissolves quickly and absorbs fast. Soil should stay moist but not wet – it will feel springy to the touch. Fresh harvests should continue through the holidays this way.

3. Amaryllis

Amaryllis bulbs flower boldly in December, drawing energy from stored reserves. Fertilize amaryllis lightly every two weeks with a phosphorus-rich fertilizer once buds open. The stems will stand tall and colors deepen.

Cut back faded flowers, but leave foliage. A bloom-boosting fertilizer like this from Amazon promotes strong petals without excess nitrogen. The bulb will feel firm when fed right. Water sparingly to prevent rot. Getting an amaryllis to rebloom next year is easy with proper care like this.

4. Christmas Cactus

Christmas cacti bloom in December, then shift to foliage growth. Fertilize lightly after flowers drop to fuel new green growth. A balanced houseplant fertilizer diluted to half and applied every month works well. Your plant should stay plump and ready for next year's show.

Avoid overwatering during feedings. An Epsom salt mix like this from Amazon for magnesium helps if Christmas cactus leaves turn purple or red. Foliage will feel waxy when healthy and light from an east window aids nutrient uptake. Fertilizing Christmas cacti this way will aid recovery from bloom stress quickly.

5. Cyclamen

Cyclamen bloom through winter indoors, but they need consistent nutrients to produce those ruffled flowers. Fertilize every 2-3 weeks with a low-nitrogen formula at quarter strength. The petals will hold color longer and leaves stay green.

Cool rooms suit cyclamen best. A diluted houseplant fertilizer prevents lush growth that's prone to pests. Tubers should feel solid below the soil. Bottom-water to keep crowns dry and prevent rot. Blooms will extend into spring with careful fertilizing of cyclamen plants.

6. Paperwhites (Narcissus)

Paperwhites forced indoors grow fast in December, so they benefit from a light soluble feeding during stem elongation. Add a weak all-purpose fertilizer once foliage reaches 4 inches (10 cm) . The flowers open fuller and fragrance intensifies.

Discard after flowering as paperwhites don't rebloom well. A soluble fertilizer dissolves quickly for easy absorption. The bulbs will feel heavy when properly hydrated. Group them in shallow bowls for stability. Stems stretch tall without tipping over.

7. Forced Hyacinths & Tulips

Other forced bulbs, like hyacinths and tulips, push out stalks in winter and also need soluble feed for strong blooms. Fertilize lightly once buds color up, using a diluted bloom-boosting feed. The scents will fill the room and colors will pop vividly.

Plant in a cool spot post-forcing. Bulbs should feel firm. Chill them before replanting forced bulbs outdoors for the best results. Flowers last weeks longer with a boost of fertilizer.

8. Blooming Orchids

Phalaenopsis orchids bloom anytime, including in December if cycling is right. Feed weekly at quarter strength with an orchid fertilizer during blooming. The roots absorb nutrients quickly, keeping new growth loaded with buds.

Mist aerial orchid roots daily. An orchid fertilizer like this from Amazon supports this tropical plant's needs. A bark potting mix drains fast, so pots will feel light when dry. New leaves unfold steadily throughout the cold months with proper fertilization.

9. Winter-Flowering Pansies & Violas

In mild climates, pansies and violas bloom outdoors in December. Fertilize very lightly with a diluted liquid feed, if soil tests show low nutrients. The flowers should hold through frosts and colors brighten.

Deadhead spent blooms. A mild feed prevents fertilizer burn in cool weather. The soil should feel cool yet loose. Mulch lightly for insulation. Plants spread wider with proper care, filling in nicely for gorgeous winter pots.

10. Nutrient-Deficient Houseplants

Houseplants with yellow leaves or stunted growth in December need a one-time diluted feed to stabilize and recover. Use a balanced formula at quarter strength to correct nutrient deficiencies. The color returns and growth will resume slowly.

Diagnose the exact cause first by looking at leaf patterns. Different types of yellowing signal different deficiencies. Next, a good houseplant fertilizer will revive without shocking your plant. Repot houseplants if roots are crowded and health should improve noticeably in just weeks.