Producing, harvesting and sowing seed

As euphorbia seeds have a limited shelf-life, they are rarely offered commercially.

Pollination can be achieved using a brush with fine hair, and transferring the ripe pollen from one cyathium (flower) to the stigma of that of another plant. Be sure to clean the brush thoroughly after use to avoid unexpected hybrids! Another way is to remove ripe stamens using fine tweezers and using them immediately to effect a pollination.

Pollination of Euphorbia bupleurifolia
Taking pollen of a male plant	Transferring pollen to the stigma	Using tweezers

Harvesting seeds presents a problem. The fruits of euphorbias are hard, woody capsules, made up of three segments, each containing a relatively large seed. When the capsule ripens, it explodes and scatters the seeds over amazing distances. A tried and tested method is to put a cotton pad around the ripening capsule and so prevent the seed from flying away. Nylon stockings can be used in the same way. In the case of particularly valuable seed, the whole plant can be enclosed in thin gauze or nylon.

Seed capsules
Euphorbia bemaharensis	Euphorbia geroldii	Euphorbia maleolens	Monadenium pseudoracemosum

A convenient and safer method to save the seed is to apply a thin layer of glue to the already ripened capsules to prevent them bursting open. Fully dried capsules can sometimes be collected whole and opened carefully from the base.

Applying a glue layer

Euphorbia and Monadenium seed
Each photo shows an area of 7 x 7 mm
Euphorbia alfredii	Euphorbia groenewaldii	Euphorbia lupulina	Euphorbia meloformis
Euphorbia nubigena	Euphorbia pugniformis	Monadenium coccineum	Monadenium mafingense

Containers suitable for sowing are above all shallow plastic pots or trays as they do not dry out so quickly and can easily be cleaned and disinfected. The sowing medium should be light and poorer in nutrients than normal commercial plant compost. A mineral soil can also be used, such as fine to medium grade sand to which can be added a little finely sifted peat. The soil should be thoroughly wetted by standing the containers in water.

As conditions in the containers are also favourable for fungus growth, sterilisation of the soil is recommended (about 20 minutes in an oven at 120 °C with the soil evenly spread on a sheet). The soil can also be disinfected with a fungicide such as Chinosol, but please read the directions carefully or the tender seedlings may be damaged as they germinate.

Fungus in sowing soil

Sow the seeds evenly and not too thickly on the surface of the soil, press lightly and cover with a very thin layer of soil or sand no more than twice the thickness of the seeds.

During the period of germination, always keep the soil moist as letting the soil dry even once can result in heavy losses. It can be helpful to cover the trays with a transparent plastic dome or cling film.

The temperature at night should not go below 18 °C, although by day it can rise as high as 40 °C. 25 °C is ideal. Basically higher temperatures bring faster germination, but full sun should be avoided to prevent the young seedlings scorching.

Raising seedlings in a box
Sowing box	Containers and pots	Soil thermometer	Germinated seedlings

The short viability of euphorbia seeds should be noted. The percentage germination can fall to 50% after only a few weeks. In general seed needs to be dry and stored at 5 °C in air and water proof containers. Dampness or higher temperatures cause the viability to decline more quickly.

As rainfall is irregular in habitat, not all seed germinates at the same time to ensure some seedlings survive. Germination tends to occur in waves, for example after one week, 8 weeks and 15 weeks. Furthermore, the germination period also varies from species to species.

Seedlings
Euphorbia alfredii	Euphorbia brevirama	Euphorbia bubalina	Euphorbia enopla
Euphorbia gottlebei	Euphorbia meloformis	Euphorbia rossii	Euphorbia thinophila