Your plants basically need two types of nourishment to survive: water and minerals. They get minerals by absorbing them from the damp soil through their roots. Outdoor plants can often gather all the minerals they need from their surroundings by themselves. However, houseplant care requires more careful attention from the gardener, since the nutrients available from the soil in a pot are limited.

What do those numbers on the fertilizer bag mean?

The key elements required for plants are Nitrogen (N), Phosphorus (P), and Potassium (K). A fertilizer bag shows the percentages of these three nutrients as three numbers, always given in the same order. An example: an 18-6-12 label means that the bag contains 18% nitrogen, 6% phosphorus, and 12% potassium, usually in the form of nitrates, phosphates, and potassium salts. Other nutrients are also needed, but their required amounts are much lower.

How much of each mineral does my plant need?

This of course depends on what type of plant you are fertilizing. It is very important not to give your plant too much or too little food. This is a decision that must be made for each individual plant. You should carefully read both the label that came with your plant if there is one, and the label on the bag of fertilizer. If you’re still not sure, ask the person at the plant store for advice.

What is the function of each of the primary nutrients?

This topic is continually being researched by scientists. For the purposes of gardening, we can say that phosphorus is needed in greater amounts for flowering plants, while leafy plants like plenty of nitrogen. Potassium is particularly required for plants that bear fruit, since it helps to carry other nutrients through the plant tissues.

What are the symptoms of poor feeding?

A nutrient deficiency will often cause the leaves to lose color, or to be smaller than normal. To help the plant recover, use a soluble fertilizer, so the nutrients can be absorbed faster. Too much fertilizer can result in brown leaf tips, or in wilting. This condition is easily relieved by soaking the whole pot in water to allow the excess nutrients to be washed away.

How and when do I apply fertilizer?

Personally, I prefer fertilizers that are dissolved in water, as this method is less likely to result in over-fertilization. I mix the fertilizer according to package directions, and then apply it by thoroughly watering the plant, until it flows out of the drainage holes in the bottom of the pot. I find that doing this about every two months is usually just about right.

If you use care in feeding your house plants, they will not only stay alive, they’ll become luxuriant. And don’t forget to ask for advice if you’re having difficulties. Your plant store should be happy to help a good customer.

Do you need more advice on tropical houseplant care? Visit the Professor’s website on tropical houseplants, where you can find help for your plants. I also have a lot of beautiful photos, and some neat videos too.