Andrew runs Orchid Alchemy and produces/sells lots of young plants, so is well placed to talk on this subject. He started by saying that there are around 500,000 Orchid species and hybrids from all the continents apart from Antarctica, and therefore there should be something available for everyone to grow. There are 3 stages of Orchidology that we have all fallen into; 1. Acquire one or more plants Discover that they will grow and thrive. 2 Buy more, and become hooked. 3. Buying young plants is the cheapest way to extend a collection, and it brings the thrill of a first flower – which could be different. It should also be vigorous and grow quickly. He has 3 golden rules for successful growing – 1 Visit growing areas frequently to check conditions – temperature & light etc. 2. Collect rainwater – essential to add nutrients for feeding, unlike tap water. 3. Never stop learning. Every year, and season is different, and predicting patterns is impossible.
The life cycle of the orchid is different to most other flowering plants, and varies enormously from one species to another. Orchid pollination is a story in itself with a variety of pollinators, but once pollinated can take from a few weeks to 18 months to ripen and be ready to sow. There can be up to 3 million seeds per pod, and if you assume that the wild population is stable, then survival rates per seed are about 3 million to 1 (In the Lab it is quite easy to get many to grow). Seeds are generally wind distributed, and are shaped to assist distribution. In cultivation they are distributed more by AirMail!
The seeds themselves are very small at between 0.03 – 0.08mm in size, and are under developed embryos. They contain no endosperm and therefore they require nutrients to germinate. This is achieved by attaching themselves to a fungus where they are termed parasitic for their initial development. In cultivation generally they are grown in vitro in a sterile environment. The technique to achieve this was developed in the 1930s with an agar mix containing small amounts of soluble fertiliser, vitamins and some proteins for energy. Variations on the theme have included banana, pineapple and coconut. Once sown, the seeds can take years to germinate. They need the right temperature and a mixture of light and darkness, although they are unable to photosynthesise for a long time until they develop a green leaf. The energy is created from the sugars in the agar extract. The sterile environment in the flask is the best place for a seedling to develop, and including re-plating it should be left to get as big as it can, which may well include the first ‘bulb’ or so. De-flasking should take place in the season when the roots start to grow. Wash the agar off and separate the plants if possible. If not it doesn’t matter. Pot up with fine bark. The plants will still be very tender for at least 2 weeks, so they should be hardened off slowly with 50% shade and 70-78% humidity. They should get a watering with a continuous weak feed until becoming established. Young plants don’t want a rest period as they have no established reserves, so push them along until they are of a sufficient size (a mature growth) to withstand a rest – this may take a couple of years. During this time they can be relocated to suitable light levels, but continuous checks should be made on colour to ensure they are growing correctly. Light or dark colours will indicate too little or too much feed, and this should be corrected. Although not requiring a mature plant environment the seedlings still require a night time temperature drop of 5C.
In their native habitats orchids thrive in nutrient poor areas. This is due to their efficient take up of nutrients. As they are unable to prevent this absorption they will die if given too high a nutrient level. This is vital knowledge when watering and feeding. Added salts etc in tap water means that adding fertiliser can reach too high a tolerance. Where possible, collect rainwater or use distilled water (RO) to allow a sufficient level of feed to be used. If in a drought and there is no rainwater available then tap water can be used, but no fertiliser added, and flush frequently to prevent a build up of salts. Remember that ‘cold water kills’, so ensure that the water is at greenhouse temperature prior to use.
Young plants should be in a fine compost. Many composts (or potting media) are available, and you should use whatever suits you and your environment, but don’t forget that composts change over time – from bag to bag, and year to year, as well as decomposing over time. Adults need re-potting every 12-18 months, and seedlings more frequently (into larger pots). Young plants often have juvenile foliage, so may not look like you expect, but you should allow room for 2 years growth to allow for e.g. Phalaenopsis leaves to smother the surface area and prevent watering. It also prevents drying out. Experience will help in this regard between suitable pots and over potting.
Generally mature plants need 60-80% humidity, the same as most other plants, and this is temperature dependant. Higher temperatures need higher humidity, and this in turn needs a higher rate of air movement. This can be key to watering. Plants should only be watered when necessary, and this includes assessing water loss (evaporation and uptake) and compost age to those above. Don’t forget that the environment is our responsibility as we control it. Getting it wrong can be fatal. Don’t be put off though!
The length of time that a plant will take to flower from de-flasking can vary enormously. The fastest is Cynorchis at around 6 months, Barkeria at 12 months, and Dendrobiums from 18 months. These are obviously more rewarding than others which can take over 10 years. A reasonable average is around the 3 year mark. There is a great advantage to growing plants from flask or buying as a seedling, and this is that they should be strong and vigorous, free from virus and have multiple growing nodes to bulk up. They will have varied genes which are required to help the species survive. Plants sourced from divisions may become the opposite of this. It is also possible to get more rare and unusual species from flasks which may be the only way to import plants without breaking CITES. Never stop learning is the final point, and can’t be over emphasised. Remember every year is different, and the plants need to react to this, and so do you. As the environment changes, so should you! “You need to talk to your plants, but you also need to listen to them” is a good way of emphasising the point.