Greenhouse Calendar

April

During March many of our plants have begun to show signs of growth and, to encourage this, they should have been sprayed with tepid water on sunny days. As we go into April many cacti will begin to flower and, provided the weather is bright and sunny, a light watering can be given. Watering should be withheld from Echinocereus and Lobivia until the flower buds are fairly well advanced. It should be possible to give the first really good drenching towards the end of the month. Many of the other succulents will also benefit from a similar watering regime but Conophytum should not be watered nor should caudiciforms until they show signs of growth. Lithops can be watered when the old leaves have shrunk sufficiently. Do not use pesticides in the first watering.

Late March and April is also a good time to sow seeds. I find that seeds sown in April soon catch up those planted earlier in the year The method I use is to fill 50mm pots about 2/3 full of my standard compost then cover with a layer of seed grade vermiculite. I then stand the pots in a tray in a tray containing a copper based fungicide solution. Do not use Chinosol because it has a tendency to inhibit germination. I sow the seeds on top of the vermiculite and, if the seeds are fairly large, I sprinkle vermiculite thinly on top. I then seal the pots in polythene bags until germination has taken place a few days to a few weeks later. I find that cacti can be left in their polythene bags until they are quite large perhaps for a year or so. Many other succulents do not like this treatment and do better if they removed from their polythene bags once germination has taken place.

By the end of the month most plants will be growing strongly. If I find any that are not doing as well as I think they should, I examine them, carefully checking for pests and/or root loss. If I find that root loss is the problem I cut away any dead roots, leave to the plant to dry for a week or so then set the plant in a peat and sand mixture.

Greenhouse Calendar

May

Most cacti and indeed many of the other succulents will be in full growth by the middle of the month and, provided that the weather is bright and warm, will need to be watered regularly. How frequently depends on how warm the weather is. The hotter it is the more frequently will the plants need watering and do not forget that small pots need watering more frequently than larger ones as they dry out more quickly. I like to feed my plants at every watering at this time of year and this is also a good time to give them a good dose of systemic insecticide.

Your lithops will be ready for their first watering sometime this month if you have not watered them already. I like to give my conophytums a drink sometime during the month and then I wait until the end of July or early August before I water them again. There are exceptions of course; Conophytum smorenskaduense has only just flowered so doesn't need watering until later and Conophytum reconditum, with its minute bodies, needs watering for most of the year and is actively growing at the present time.

This is a good time of year to take cuttings and to graft seedlings if you are that way inclined. Once the frosts are over a number of cacti and succulents can be moved out of doors. The winter flowering Schlumbergeras etc benefit from a summer outdoors in a part shaded position. Also I keep some agaves, opuntias and crassulas outside during the summer but in a position where I can protect them from rain.

Finally, now is the time to think about cleaning up in the greenhouse because plants can be taken outside for a while. I like to clean the glass inside and out at this time. It is surprising how much algae can grow on the inside of greenhouse glass.

Greenhouse Calendar

June - July

The late spring and early summer are the times when there are most flowers in the cactophile's greenhouse. It is also the time when there are many shows up and down the country where one can go and see the fantastic range of plants that are available these days. Hopefully there will be plenty of sunshine during the coming month although this brings with it dangers as well as benefits. For example some Copiapoas suffer from sunburn if they are left in the full sun under our greenhouse conditions, This is because in habitat they are protected from the sun during parts of the day by mists that roll in from the Pacific Ocean. Lithops too can be boiled to death if they are left fully exposed to the sun in our greenhouses. This is because, in habitat, they are partly or totally buried in the soil at the hottest part of the year and also ventilation is much better, The remedies are firstly to partially shade your greenhouse and secondly to provide as much ventilation as possible, Some plants do their best to protect themselves from these extreme conditions by going dormant in very hot weather and this has implications as far as watering is concerned. I tend to cut down on watering for some plants during very warm weather particularly if the night temperature does not fall below about 15 C in the greenhouse during the night. In any case always make sure that pots have dried out before watering. If a plant has become dormant the pot will not dry out so quickly. Never assume that a pot will have dried out simply because the ambient temperature is high.

Most Lithops and many other mesembs will be in growth by now so they will need watering and maybe feeding. Lithops do not require a great deal of fertilizer so whether or not you feed them at this time depends on whether they were repotted during the winter. If they were they will not need feeding; if they were not, dilute feed can be given between now and the flowering season. If Lithops are overfed they are likely to grow over large and out of character. Some Conophytums particularly those with small bodies should be watered lightly to prevent excessive shrivelling - the bilobes can be left for a while yet otherwise unnatural double leaf pairs may result. Some growers advocate a rest from watering for Haworthias during the summer. This will help to develop the natural red colours in the leaves but, if you prefer them green carry on watering and partly shade the plants.

Finally if you are going to enter any of the shows now is the time to make your selections and to clean up the plants and pots remove any unsightly flower remains and give them some new top dressing.

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