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Fertilizing indoor plants

Weeping fig tree
Photo: Jardin botanique de Montréal (Normand Fleury)
Ficus benjamina 'Variegata'

When to fertilize indoor plants

Indoor plants should be fertilized when in active growth, usually from March to October. Soluble fertilizer may be applied once a month to fast-growing plants, and every other month to all others.

In general, it is best to wait one month before fertilizing a newly repotted or purchased plant. 

Recommended fertilizer for different types of plants

Fertilizer labels show three figures, representing the percentages of nitrogen (N), phosphorous (P) and potassium (K), in that order. The most useful formulations are 20-20-20, 10-30-20, 15-30-15 and 30-10-10.

Remember to dampen the soil before adding fertilizer. Never fertilize a sick plant.

Type of plant Formula
Foliage plants 20-20-20
Ferns 20-20-20
Apply fertilizer at half-strength
Cacti and succulents 10-30-20
Flowering plants 15-30-15
Acid-soil loving plants 30-10-10

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