Growing from seed

Cameron McMaster
Wed, 20 Nov 2002 03:08:46 PST
We grow mainly SA species, so we have one standard method!  No greenhouse, only some shade cloth over some of the open beds, and some tables with glass-fibre roofing to keep the heavy rains off seedling boxes.  Mostly we use seed trays that are about 20x30 cm and about 10 cm deep. We prepare more trays than needed at the moment, because often unexpected seeds arrive and they can then be sown immediately.  

The mix:  First some coarse stuff, whatever is available at the time, such as composted pine bark, stone chips, broken up styrofoam to a depth of about 3 cm.  Then fill with the seedling mix: equal parts of loam, compost, coarse sand and fine composted pine bark (lumps removed or crushed).   We add a little bonemeal.  This mix is for the summer growing bulbs, but the Western Cape winter growing bulbs need more sand, so those trays get a double portion of coarse sand.  Then we pour about 11/2 litres boiling water over each tray to kill off the weed seeds and hopefully any other pests.  The final topping is:  mix in a cupful of palm peat to the top 3 cm of mix - I just stir it around into the mix.  Then I remove about 1/2 cm of the topping.

If there are a lot of seeds, I sprinkle them on the seed tray, sometimes up to 250 seeds, but if the seeds are precious or not so many, then I make shallow rows and drop them along the rows.  Different species can be sown together in rows, just make sure they are very different so that the bulbs/corms are easily distinguished when lifting them later.  The seeds are covered again with the top layer that was removed, and patted down slightly before watering carefully with a fine rose.  As with Gary's method, some coarse grit on top is beneficial.  It helps to keep the seeds firm so that they don't roll around or surface so easily. 

If there are really a lot of seeds, then we also sow in open beds, very much as Gary described.  Our water is from a borehole, so far it seems to be quite good (hasn't been tested).

We find that seedlings of deciduous species often stay green through the first natural dormant period, but we water them less at this time.  If the leaves start turning brown, we stop normal watering immediately, but still give them a very light sprinkling about once in two weeks - most of the SA species do not want to be bone dry during their first dormancy.   An advantage of using large seed trays or troughs is that the bulbs can be left to grow for at least two seasons, and if not sown too thickly, even longer.

Once I experimented with Zantedeschia aethiopica seed and put them in some damp vermiculite in a closed plastic bag in the fridge  (they germinate and grow in the Cape winter).  I forgot about them for about two months, and then found them germinating beautifully - 100%!  They normally germinate quite easily, so this was just to see how they would react to constant cold.

Cyrtanthus seeds are floated on water (start off with very warm water) for 3-4 days, then carefully sown in rows and covered as described above.  I don't wait for roots to emerge because that means a lot more work (time!) planting them out.

 The Croft Nursery Eastern Cape

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