General practice of fertilizing your foliage plants should be to apply fertilizer every 1-2 months while growth is rapid, and once or twice only during the winter months. An alternative program would be to apply more frequently at half the recommended strength: this accommodates plants which might be injured by full strength applications.
For young, actively growing plants, feed about twice as often. That is, about three weeks during times of maximum growth(say March to October) and every month or six weeks in winter.
A new foliage house plant in large planters should be allowed to adjust for at least a month before you begin fertilization. So also should newly potted plants, to give them time to grow new roots which will absorb the fertilizer you are going to apply.
WHAT KIND OF FERTILIZER?
Soluble compounds are easy to apply ans show quicker results than slow release solids. Any prepared mixture for house plants is fine: for general use, an N-P-K analysis ratio that is close to 1-2-1 will give balanced growth. Simply apply the fertilizer solution in place of water, when you normally would be watering the plants.
Use the fertilizer at or weaker than the recommended strength of dilution, never stronger. Newly rooted cuttings and young plants will benefit from weaker solutions, to avoid burning the soft young roots.
CAN I MOVE MY PLANTS OUTDOOR IN SUMMER?
Yes, if you’re lucky enough to have a porch, semi-shaded border, or other partly sheltered position where the indoor plants will thrive in warmer weather. Any time the night temperature stops above 45 degrees is fine for moving the plants outside.
Tall plants and vines will need extra support if they are exposed to wind. Heavy rains can damage delicate leaves, so overhead shelter may be needed.
Move the plants back indoors before nights get as cool as 45 degrees again.Before taking them in side, it is a good plan to wash your indoor plants thoroughly with a fine spray of water: this will was off most insects and disease spores which, in the climate of your living room, could multiply alarmingly.