We saw our first native British orchids of 2018 today on the Dorset coast. They are not in flower yet, of course, but the Early Spider Orchids (Ophrys sphegodes) on the Purbeck Coast (You may just make out Durlston Light House in the distance) have already made strong rosettes of leaves and are thinking about sending up their amazing flowers.
Plants are usually at their peak around mid-April and so with that spring like thought I will leave you with a photo of them flowering last April.
Early spider orchid on the Purbeck Coast
Pleurothallis grobyi is a delightful miniature species recorded from as far North as Mexico and as far south as Peru and Brazil. The clone we have here in cultivation originates from Ecuador but we have seen different forms of the species in Brazil, Belize and Guatemala. We have found the species in both mountain cloud forest and shaded spots in hot lowland forest and so this is a very variable species or possibly one that should be spilt into several separate species.
The diversity is shown by some of the plants we found growing in Brazilian cloud forests around Macae de Cima in 2005. These included dark yellow striped forms, creamy forms and white forms.
All of the plants we found were growing in primary forest in shade with abundant moss growing around them suggesting that plants appreciate being grown wet and shaded in cultivation. We grow plants mounted on cork, in baskets and in pots and they succeed grown all of these ways with daily watering in Cool Americas.The picture below shows Callum Swift with a plant he found on a fallen branch that shows the conditions the plant grows in perfectly.
The plants we have found in lowland forests in Guatemala and Belize are restricted to mossy patches on dead fallen trees and branches and so are growing heavily shaded and much damper that the surrounding forest. The plants here also had shorter rounder leaves and whitand pink flowers. (Below)
Whichever the form, this is definitely a species to look out for.
With the European Orchid Show in Paris just seven weeks away Gareth and Issy have spent a busy Saturday building display blocks for our exhibit. They have done a wonderful job and we now have two new triangles for our display posters and four 4ftx4ft display boxes. I can’t wait to see how they look in Paris. Without the amazing commitment of students, parents and volunteers there wouldn’t be an Orchid Project.
Today we have a modest little orchid with the delightful attributes of being easy to grow, quick to propagate and blooming throughout the year.
Pleurothallis stenosepala is native to wet forests all down the Andes from Venezuela to Peru and is found at altitudes from 1100-2600m. We grow plants in our Cool Americas section where it thrives in small pots, baskets and mounted. It produces attractive heart shaped leaves up to 7cm long and these produce successive flowers at the leaf axils.
Plants freely produce keikis on older leaves that can easily be separated as new plants. As a result this is one of the first species we give to new students joining the orchid project and many have plants growing well on their windowsills at home. We have to keep an eye out for plants growing as ‘weeds’ on other orchids where keikis have fallen and made a new home for themselves – what a nice problem to have.
A rainy day in January seems like the perfect time to talk about water. We are often asked about the water we use and how often we water in the school greenhouses, so here are a few of our basic principles.
1.Rain water not tap water. We only ever use rain water at Writhlington. We collect more than enough from the roof of the greenhouse and store it in our 16000litre rainwater tank at the back of the greenhouse.
2. We pump our rain water into a 1000 litre feeding tank in the greenhouse where we add plant food and let the water warm up to greenhouse temperature.
3. We feed with a high nitrogen feed but at very low concentrations. Generally we feed with every other tank of rainwater. This allows for washing out any salt build up. We add half a jar of dry feed to 1000 litre which gives us a conductivity reeding of about 300-400 micro-seimens/cm. This is around 1/4 strength recommended on most commercial plant foods. We water heavily and so week feed often makes sense as well as avoiding a salt build up where water evaporates.
4. We water daily for most of the year but twice daily if the weather is particularly hot and dry (Usually from late May until the middle of July), Watering involves training a hose around the greenhouse from the feeder tank and ‘making it rain’ we focus more water on plants that are mounted, in baskets or noticeably dry. We avoid plants that we have identified as liking it dryer, are in a resting period or are clearly still wet from previous waterings. Plants in pots generally need much less water than mounted plants or those in baskets. Little pots need watering more than big pots.
5. We alter water availability with plant placing and compost selection. A good general rule is that the higher the plant is the dryer it grows. Firstly watering upwards is harder (especially if you are small) and secondly the higher parts of the greenhouse are hotter and dryer. We use a really open bark compost to give excellent drainage of our heavy watering and add dried sphagnum moss sparingly if we want a particularly damp compost (though too much moss risks the plant becoming dry and staying dry)
6. We never damp down. Damping down a greenhouse to keep it cool and increase humidity is widely recommended. We find that damping down wastes water, makes the floors green and dangerous, keeps humidity too high and encourages rots in plants. We like our plants to have damp roots but live in airy conditions where they can photosynthesise effectively and that are comfortable for people too. Our recording of hunidity in tropical forests has shown that it falls to 50% during the heat of the day in and so we do not worry about low humidity in our greenhouse.