One of the biggest challenges in an environmentally friendly greenhouse is the control of unwanted pests that are potentially harmful to the plants' growth. Many of these pests in the greenhouses are now controlled biologically.
Biological control has become a very popular method for preventing damage to plants by unwanted pests, such as, spiders, thrips, aphids, and worms. Predator insects are used to attack the pests or interrupt the mating cycle to prevent the population from growing out of control. This process reduces the amount of pesticides required in flower production and thus is beneficial to the environment by reducing harmful chemicals from entering into the streams, ponds and lakes. Humans also benefit from this method because it keeps the greenhouse cleaner and free of harmful residues left behind after spraying.
There do arise situations in the greenhouse where pests can cause damage beyond control of the biological population. Certainly, in the hot summer season pest populations thrive and become very hard to keep from harming the crops. Then, and only then, do the growers need the assistance of chemicals to get the pest populations reduced to a point where biological predators can continue the control. Only chemicals that have been registered, regulated and approved by the government are applied. Chemicals used properly in the greenhouses are considered legal and safe to humans. In addition, growers in the nursery are required to have a pesticide certificate to apply chemicals. This certificate is issued by the government upon completion of an intense course on chemicals and their proper use.
Many new chemicals used for growing are naturally occurring products in the environment. For example, some controls used are in: a garlic base product, a neem based product, which come from a neem tree in Asia, a sulphur based product and a seaweed-based product. Many of the harsh, broad-spectrum insecticides are not used to grow the crops because of the harm they cause to the environment.
Another method of keeping the environment clean is reduced usage of synthetic fertilizers by applying a large amount of naturally occurring fertilizers such as manure and compost. When the flowers are harvested and brought to the grading room the 'green manure', which consists of leaves and stems which are unusable for sale, are mulched and composted and reused in the nursery for the fertilizer requirements of the crop.
Also, improvements in cultural practices such as growing hydroponically in containers or buckets, aid in the relief of the concern for the environment. This growing method allows the grower to control the amount of fertilizer each plant receives and thus helps to reduce excess fertilizer from running into the ground. Prior to hydroponic growing, large amounts of excess fertilizer were needed to grow the crop in the ground or soil. In the near future the grower will be collecting the excess water run-off from the crop, and reusing it to reduce and possibly eliminate fertilizer from running into the ground.