Most of the plants that we put into our gardens are able to obtain their nutrient requirements on their own using the available sunlight and what is in the soil. This is not the case for indoor plants, however; they rely on us to water them and provide the required nutrients.

The estimates of professionals suggest that some 90% of indoor plants are not watered properly - either obtaining too much water, which leads to root rot and other diseases, or obtaining too little. It really isn't difficult to get the amount correct, though. There are some simple tips to look out for to ensure that your plant receives what it needs.

A hygrometer is an excellent investment to make if you are serious about the welfare of your indoor plants. These instruments can cost you a fortune or be very cheap, but they will all do the job equally well.

Some are digital which means they are easy to read and are very accurate and some also contain a thermometer. This can be used to measure the soil temperature, which is another important element in the care of your plants.

There are other very simple ways of checking the water levels. Pressing a finger into the surface of the soil will indicate the amount of water in the pot. Obviously, a wet finger means water is present, but you are also testing for how much water there is. Remember that soil that is moist will "give" or feel spongy, whereas dry soil is hard.

A tongue depressor or chopstick is also a great tool for testing the water content of the soil. If, after placing the implement into the soil for a short time, the wood is dark, you will know that there is water in the soil.

There is another tried and tested method to use. This involves placing a saucer under the pot and then filling the saucer to about 1/3 of its capacity. The pot should then be left to soak up the water in the saucer through capillary action. Continue this process until there is still water left in the saucer and therefore the pot has reached its soak point. Mop up this extra water with a towel and make sure that you have kept a record of the amount of water you have placed into the saucer as this will be a good indicator of the moisture requirements of that particular plant.

In taking care of plants such as cereus peruvianus, for example, checking the amount of water in the soil doesn't involve the disturbance or modification of the soil in any way. We all understand that dry soil weighs less than moist soil, so a simple test is to place the pot on a scale and repeatedly check the weight after the addition of water. Once you have established the "right" weight of the pot, it will be easy to check if the water level is correct by weighing the pot each day. After a time, you will have an idea of the requirements of the pot for and you won't have to weigh it any more.

It should also be noted that, whilst the measurement of the water volume is a good guideline, there are other variables that affect plant growth like cactus plants such as air temperature and humidity due to seasonal changes that will dictate the amount of water required by the plant. As such, using a combination of checks and balances should ensure that your plant remains healthy all the time.