Articles Written By Members and Associates

The Importance of Correct Watering

In my humble opinion correct watering is the most important part of growing fuchsias. A well-known old fuchsia grower once said to me that the secret of growing good show bench fuchsias was 90% correct watering and 10% skill.

Fuchsias are like human beings, that is, they can go a long time without food, but only a short time without water. Water is contained in all parts of a fuchsia. Young shoots and root tips are 90% water, while the main stem and branches are up to 50% water.

All the living processes in fuchsias take place in water, e.g. sugars are built from carbon dioxide and water. And minerals and nutrients are carried from the growing medium through the roots to leaves in a flow of water. In spring the sugars and amino acids are carried by water to the new growth. The process by which water flows is called transpiration. The energy for transpiration is provided by the sun, about 50% of solar energy landing on the foliage is used for transpiration. Evaporation of water through small leaf openings, called stomata, causes more water to rise from the roots. Carbon dioxide is absorbed into the leaves via the same openings. It takes 55 grams of water to produce 100 grams of plant fibre, but in the time it takes to increase its weight by 100 grams about 100,000 grams of water is used due to transpiration or evaporation through the leaves. For photosynthesis to take place transpiration must bring water from the growing medium to the leaves. Carbon dioxide must be dissolved in water to enter through the cell walls. The surface of the chlorophyll-containing cells must be kept moist at all times. After reading this paragraph I hope you will appreciate the importance of water in the growing cycle of the fuchsia.

Fuchsias have a water regulation system that permits a plant to shut off the stomata and thus prevent loss of water. At the same time the stomata have to be open to admit carbon dioxide for photosynthesis, therefore the plant has to balance between loss of water and assimilation of carbon dioxide. The stomata are open in the early morning, at about midday they begin to close, and just before sunset they are closed. During very hot days, temperatures of 80F and higher, the stomata are open for only a short time in the early morning and then closed for the rest of the day. Likewise the same things happen if the plant is short of water - the stomata will open for only a short while, to conserve water. Under these conditions the plant processes of transpiration and photosynthesis stop and the leaves are no longer being cooled by evaporation, so the plant wilts. The first thing we think about doing when we find a plant like this is to water it. This can cause us to over water the plant and kill it, because as explained earlier, the stomata being closed, the plant cannot draw water up to the leaves easily, if at all. The best thing to do to a wilted plant in summer is to mist the leaves to cool them and this should be repeated several times and should be done on hot days to prevent wilting also. Regular misting in hot weather also helps to keep the stomata open longer and thus give more growth. It should now be obvious to all reading this the importance of watering first thing in the morning over watering later in the day. Indeed, if you water at night you can do more harm than good, because the stomata are closed and thus the roots are lying in water all night and can rot.

I was confused as to how my plants did not grow as fast or strongly as a friend's who lived not far from me, and tried to copy his methods with no more success. However, when I copied his growing conditions and studied the above information, the answer came to me. He grew his plants on a bed of sand which was in a cover of polythene so that he could keep it moist and the water level just below the surface of the sand. My plants were on a wooden bench in a dry greenhouse, but my plants had plenty of water. The reason his grew better was the humidity caused by the water in the sand keeping the stomata on his plants open longer, and thus the living processes were working better than mine where the stomata were closing earlier.

Small gravel chips can be used in place of sand and work just as well. This year I did an experiment and grew half on sand the half on the dry bench and the result was spectacular. The plants grown on the sand grew far quicker and better than the ones on the bench. There is a gentleman who lives in the South of Scotland who regularly floods his greenhouse floor and when you open the door to walk in it is like walking into a sauna, but the growth he gets is amazing. The importance of a moist atmosphere cannot be discounted if you want the best out of your plants.

When my cuttings are young and just potted up I only moisten them, as I lost a lot of cuttings due to them lying in wet growing medium and the small plant and roots being unable to take up the water it was given, thus making the roots rot. However, later in the season, when the plants have established good root systems, I plunge them into a bucket of water, containing a weak feed, and wait till all the bubbles have stopped before replacing on the sand bench. The same applies to plants in the garden and you should ensure that in dry weather you water them in the morning and if possible give a regular spray in hot, dry weather.

FR (Inverness, Scotland)