When To Start Fertilizing Indoor Plants

The best time to begin fertilizing any plant is at the beginning of its growing season. Typically, this means early in the springtime after a winter season of rest. 

This is true even for indoor plants because they can sense the lengthening of days that spurs new growth. 

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The exception to this is indoor plants kept under grow lights through the winter. These plants can be fertilized year-round. 

Fertilizing Indoor Plants Q&A

1. When should you stop fertilizing indoor plants? 

Generally speaking, in areas where winter days are quite short and nights are quite long, it’s a good idea to stop fertilizing in October. 

2. How do grow lights affect a plant’s need for fertilizer in winter? 

If you are lighting in a way that provides your perennial houseplants 12 hours a day of good, strong light, they will be able to continue growing normally. In this case, they will need fertilizer just as they do in spring and summer. 

3. If a houseplant continues to grow in winter, even without extra lighting, does it need fertilizer? 

It’s best not to fertilize slowly growing plants not kept under grow lights in the wintertime because the resulting growth is likely to be weak and pale. 

4. Why not fertilize in winter?

Most plants go into a state of semi-dormancy or full dormancy when the days get shorter, the nights get longer, and temperatures begin to drop. They do not need extra nourishment during this time and cannot process and use fertilizer while at rest. 

5. What should you do if a resting plant produces new growth? 

It’s actually best to keep winter growth pruned off so that the plant can conserve energy. This helps ensure that springtime growth will be stronger and more robust.

6. What month is best to begin fertilizing in spring? 

The days typically begin lengthening toward the end of February and the beginning of March. This is when you will typically see new growth on plants that have been at rest through the winter. When you see new leaves begin to grow, provide the first dose of fertilizer. 

7. Can you encourage plants to put out new growth by fertilizing? 

You can do this, but it’s not the best idea. Rather than pushing your plants to grow, think of rewarding them when they do. For example, if your plant actively tries to create new leaves and stems, it tells you it could use some food. 

8. What if my houseplant begins creating new growth very early in the spring? 

If your plant starts growing new leaves early in February, go ahead and feed it!

9. What kind of fertilizer is best in early springtime? 

Any good quality, balanced, general-purpose houseplant fertilizer will do just fine. 

10. How much fertilizer should you use? 

It’s always a good idea to fertilize lightly. Too much fertilizer can burn roots and stems and spur rushed weak growth. On the other hand, a half or a quarter dose of fertilizer will probably give your houseplants just the right amount of nourishment for healthy springtime growth. 

Why Do Houseplants Need To Rest In The Winter? 

Not all houseplants do need a rest in the wintertime. Perennial and deciduous plants that naturally shed leaves and cease growth during cold weather need a time of dormancy. 

These plants might overwinter in your basement or other protected, cool, but not freezing setting if you live outside their correct USDA hardiness zone. 

Tropical plants that would grow all year round in their native settings will happily do so in your home as long as you can provide them with consistent warmth, humidity, water, and ample light. 

What usually happens for these plants in winter is that their living conditions are simply not conducive to robust growth. 

The days shorten, temperatures drop below what tropical plants typically like, and humidity lessens because of indoor heating systems. 

When this happens, tropical houseplants drop leaves and slow down growth to conserve energy in the roots until conditions become optimal once more. 

This is alright. If you cannot maintain the best plant conditions in winter, you can let your tropical houseplants rest. 

Set them in a quiet, out-of-the-way place with bright, indirect sunlight, consistent moderate warmth, and judicious watering. 

When the days begin to lengthen and warm up, prune, repot, water, and fertilize your tropical houseplants and place them in areas where they can thrive. They should soon show vigorous signs of life and growth.