This Years Test Results and Extra Tips

This year we conducted 200 test sowings amounting to 1/5th of our species overall and almost of 1/3rd of those species we test ourselves rather than just relying on the certification from the wholesaler/collector/grower.

As a result of these tests we have found that all of our cacti and succulent species continue to show excellent viability.  We also tested all Acacia, Cassia, Delonix and Erythrina species again with very good results.

Cacti and Succulents

We didn't use the ziploc bag method this time, instead we went for the covered tray.  Each batch was sown in a 7cm square pot of finely sieved (3mm) compost with a 25% addition of perlite to lighten up the mix.  The pots were watered before sowing and no chemical fungicides were used.  The seeds were all surface sown, then mist sprayed to settle in.  The pots then went in seed tray (15 per tray) and had a domed cover put over the top.  The whole thing then went on a heat mat giving a 10 Centigrade (18 F) lift over the ambient temperature this being in a greenhouse with a minimum temperature of 7.5 Deg C.  Placed on the 2nd shelf of the staging, underneath the main layer, this gave the perfect amount of bright filtered light (around 40% of what was available).  This mimics the ideal conditions where these seeds germinate in long grass or under shrubs.  Temperatures on the mat varied from 17.5C to 37.5 C depending on the temperature in the greenhouse.   1st seedlings showed after 3 days, last ones after 6 weeks (for cacti) and 10 weeks (succulents).  Percentages varied from 80% to 100% which, as ever, was species and age dependent.   Anything with less than 50% we planned to withdraw from sale, happily none fell into this category.

Acacias, Cassia, Delonix, Erythinas

These had a different treatment to the one we normally use.  Instead of boiling water we mechanically abraded every single seed used and then soaked them in tepid water until they swelled to at least twice the orginal size.  We then sowed them as per the cacti - the only difference being 50% were put in bags the other 50% in trays as per cacti.  Germination was even and good across the board and we saw 60 - 100% in every tested species.  Where we noted a difference was in after care, those in the bags fared less well than those in the covered trays once they were exposed to fresh air - conclusion the bag method produces a more even germination but a less robust seedling - we recommend that the covered method is used UNLESS you have time to check every day and get any seedlings out in to the fresh air immediately they show the first leaves.

Growing Members of the Pea Family from Seed

Growing Members of the Pea Family from Seed

To grow members of the pea family (Fabaceae) from seed it, is first necessary to break the seeds
dormancy. There are 2 basic ways to do this, or perhaps use a combination of both.

One – Scarify the seed by either rubbing it with sandpaper or taking a nick out of the seed coat. This
allows water to penetrate the seed, thus speeding germination. I have taken to doing this with a drill
bit for the larger, harder coated seeds with considerable success.
Two – Soaking either by:

• Place seeds in a ceramic cup and add sufficient, near boiling (allow kettle to cool for
2-5 minutes before using), to just (barely) cover the seeds. Smaller seeds (pin head
sized) should have an equal volume of cold water added after 2 minutes to stop the
seeds from cooking; larger seeds can be left in the hot water and allowed to cool.
Continue to soak for 24-48 hours and sow any seeds that have swollen (it will be
obvious). Seeds that do not swell – repeat the process many times if necessary –
current record is now eleven!

• Seeds that have been scarified as at ‘one’ above should not be treated with boiling
water. Hot tap water should be sufficient. They should be left to soak until they have
swollen. After 48 hours, seeds that have not swollen should have a further nick taken
out of the seed coat.

Sow the treated seed in normal potting compost and keep at 18 – 25 Deg C, until germination occurs
(2 – 3 weeks or more, although I am currently seeing germination in 2 – 3 days!!). Sealing pot in
polythene bag helps, although watch out for mould forming which will quickly spoil a batch of seed.
Once true leaves have formed you can transplant the seedlings into larger pots. Like a lot of
legumes, Acacia’s and their relatives seem to resent root disturbance and growth will suffer a check at
this point and this is quite normal. When conducting later potting on, try to disturb the root ball as little as possible. Many of the bush/tree types have spines that are often concealed by the foliage, so take care when handling.

For those plants intended for outdoor culture, it would probably be wisest to plant them out in the
summer of their second year in order that they may establish themselves better if they are larger.

Some Additional Tips by Species

Some members of the pea family have been found to require additional or extra treatment – these are detailed below:

Acacias, Albizias and Entadas – all African species: 

Change the water frequently as the seed coat contains germination inhibitors which will be leached away by this process. Soak until the seeds have swollen to at least double the original size. When planting out in pots, use deep ones as most have a tap-root.

Adenanthera and Abrus: 

These seeds may need repeated treatment with boiling water as per Erythrina. For Abrus – the soaking water is toxic.

Dalbergia: 

These seeds most often come in the pod. The seeds are almost impossible to extract from the pods,
so don’t try. Soak the seed pods for a few hours and then sow them on the surface of the compost.

Delonix and Colvillea:

These are the seeds I have had to take a drill bit to. The seed is very hard and it is
important that the seed coat is damaged prior to soaking or the water just will not penetrate. Don’t use boiling water; just use hot tap water (60 – 80 degrees C or so).

Erythrina: 

The coral trees have exceptionally hard seed coats. Treat with boiling water as described over.
Soak for 48 hours changing water daily. Remove and sow any seeds that have swollen to at least double original size. Re-treat stubborn seeds with boiling water and continue to repeat this process until the seeds swell. 100% germination will occur with swollen seeds within just a few weeks, un-swollen seeds may take a year or more to germinate and can survive in the soil for 10 years or more and still be viable.

Indigofera,Lessertia & Podalyria: 

These don’t need scarifying but need to be soaked till they swell up. They may germinate in the soaking water (I once left a batch for 7 days and all germinated in the soaking cup), this is not a
problem, just sow and lightly cover and all will be well.

Kennedia:

The coral peas require a quick boiling water treatment. Add no more than 1 cm of boiling water to a
ceramic cup containing the seeds. Leave for 5 minutes then add 5 cm of cool water. Continue to soak for 48 hours. If the seeds don’t swell – repeat the process once more.

Lupinus:

These are biennials and will self seed themselves if happy. They may be sown as overleaf, or sown direct into a prepared flower bed.

Pterocarpus:

Crack the outer case and either remove the seed or leave it in situ. Use warm water for the
soaking. Failure to do this will mean the seeds will take a year or more.

Schotia and Xanthocercis:

The Boer Beans and Nyala Beans have large seeds that need a long soak. Treat with boiling water as described over, then soak, changing the water daily, for up to a week.

Wisteria: 

Sow outdoors in pots in a cold frame or unheated greenhouse. Can take up to 12 months to
germinate.