Longer Lasting Plants 

Have you purchased an indoor pot plant and found it seemed to thrive for a few months and then slowly became sick and died, even though you followed the label advice, or thought you did?

Here are some key pieces of advice to help you understand the label recommendations on houseplants.

• All plants need 4 things at the correct* levels to survive and thrive:
  • Light
  • Water
  • Space
  • Nutrients

*Correct levels are those within an optimum range.

Other than a few ephemerals, there is, in fact, almost no limit to how long most houseplants can live if you give them the conditions they require: good light, good humidity, appropriate watering and nutrient supply.

Light

It is hard for us to judge light levels in our house because our eyes and brains adjust to low light so well; we even out light levels. There may be 100 times difference in light levels between the light on the windowsill of a north-facing window in the sunshine and the back corner of the same room. Thus, a plant in the back corner can only produce 100^th the amount of food as a plant on the windowsill.

All houseplants need light to photosynthesise and produce energy food from water and air. If the houseplant label says it ‘tolerates shade’ it means it tolerates shade, not that it thrives in a dark corner. It probably means it can be damaged by long periods of direct sunlight. You may have purchased the plant to fill that dark corner at the back of the living room, and it will tolerate that position for periods, but it will need to be moved to somewhere with more light every week or two so that it can make the food it needs. For example, peace lilies and rubber plants will tolerate low light areas for a couple of weeks but give them a bright spot, out of long periods of direct sunshine, and they will thank you for it.

Plants with labels that say ‘Keep out of direct sun’ will tolerate direct sun for short periods and are likely to thrive in bright areas.

Read the label on the plant it will give you an indication of the range of light that the plant prefers.

• High or Direct Light - Sunny windows facing north or northwest.
• Medium or Indirect Light - East facing windows, and bright places in rooms away from north-facing windows.
• Low Light - South-facing windows and darker areas of rooms but with some light. Or very dark areas but in this case, move the plant to a brighter area occasionally.

Water

All plants need water, but some need more than others. Air plants may be able to survive by absorbing water from the air, but even they will die in dry air conditions because their natural habitat may be attached to a rock or tree in a steamy jungle or where dew forms on the leaves each night. On the other hand, many carnivorous plants such as pitcher plants prefer to sit in water sodden moss which simulates their natural habitat of swamps and marshes.

Most houseplants fall in between such extremes. They may wilt with:

• Too little water; the roots have dried and the plant loses turgor (water pressure within the plant) as water evaporates from the leaves.
• Too much water; over-watering and waterlogged soil can leave the roots unable to get oxygen; without oxygen, the roots lose their ability to function properly and uptake water and nutrients. The plant then loses turgor and wilts.
• The Gro-Sure Houseplant Watering Indicator takes all the guesswork out of watering; water when it shows red and don't water if it shows blue.

Most houseplants do best with a relative humidity of between 50% and 70%. Plants create a certain amount of humidity themselves through transpiration through their leaves, evaporation from the soil, and their pots if they are porous. If the tips and edges of leaves are going brown this suggests the humidity is too low. Most houseplants will thank you for the occasional misting of their leaves because our homes are generally heated and dry and plants are normally wet by rain in their natural habitats. Gro-Sure Houseplant Mist'n'Feed and Orchid Mist'n'Feed are ideal for misting and feeding your plants.

Space

Plants need space; not just for their leaves and top growth but, perhaps more importantly, for their roots.

When you buy a potted indoor houseplant, let it get used to the new environment for a couple of weeks, then you should re-pot it into a pot of a larger size. A good rule of thumb is to think of the plant being twice the size and chose a pot that would be suitable for it growing to that size; this will usually be a pot 2-3 cm deeper and wider at the rim. This ensures the plant has plenty of room for its roots as it grows.

It can be very attractive to plant several plants together in a large pot. Plant plants together that have similar requirements for water and nutrients but there may be an opportunity to put together plants of differing light requirements if the sun tolerant plant/s can be located to shade the sun-intolerant plants.

Nutrients

All plants need a range of nutrients for healthy growth. In most cases, they get these nutrients by absorbing them as salts from the soil or medium they are planted in. The main nutrients are nitrogen, phosphorus and potassium, (shown as N:P:K), but other nutrients such as iron, sulphur, magnesium and manganese are also essential. Most of these are supplied in the potting media that you will use to re-pot your plant. They can be supplemented by the addition of houseplant fertilisers at any sign of nutrient deficiencies, or preferably before.

Do not over fertilise your pot plant; although these nutrients are essential to plants, they can have too much of a ‘good thing’. Follow the advice on the Gro-Sure Houseplant Pump'n'Feed, Orchid Pump'n'Feed or Cacti and Succulent Pump'n'Feed and your houseplants will thrive.

Note: Nutrients such as those supplied in fertilisers are essential for the plant, but they do not provide energy; the energy food is the sugars made in the leaves through photosynthesis. The nutrients are required for building structures in the plant and for normal growth using the energy in the food/sugars.

Temperature

In general, houseplants are from tropical areas and prefer temperatures in the 15°C to 25°C range during the day and not falling below 10°C at night. Normally homes are kept within these ranges. For the best care of your houseplants ensure there are no sudden large temperature changes. Keep plants away from drafts, heaters, fireplaces, and cold winter window glass.

Pests and Disease

Plants that have light, water, space and nutrients within their optimum ranges are likely to be healthy and most able to protect themselves from pests and diseases. But, if one or more of these requirements gets out of balance the plant’s immune system may be compromised giving pests and diseases the opportunity to attack the plant.

If your plant looks sick it is important to first identify the cause and return the plant to its optimum habitat conditions before trying to tackle the pest or disease with the specific curative product such as a fungicide or insecticide. The Gro-Sure Houseplant Insect Control is ideal for protecting your houseplant from insect pests.

Make Your Plant Feel at Home

In general, you should aim to make your houseplant ‘feel at home’. That is, you should aim to recreate the conditions the plant has evolved into. Most houseplants’ natural habitats would be tropical, sub-tropical, semi-arid or desert. Find out where your houseplant species is originally from so that you can understand what your aims are.

Similar principles follow for your outdoor garden plants (See How to Grow Everything - General Advice on Growing Plants).

David Brittain
Kiwicare