I love carob trees (Ceratonia siliqua) and, having had some success with growing cork oaks from seed, I decided to have a go with carob seeds too.
I brought two big carob pods back from Portugal in November last year and then – because I’d read that you shouldn’t sow the seeds until the spring – I left them in a cupboard for the rest of the winter .
In the spring (12th March to be precise) I cracked open the pods and picked out the seeds. One pod was totally empty, but the other yielded eight seeds.
I’d read that you need to sand the seeds and soak them in boiling water prior to planting them, but I was too timid to do that. Instead, I put them into a cup of hot water – 50% boiling: 50% cold – and left them for 24hrs.
The next day, I popped each seed into a small peat pot (so-called, they’re not actually made of peat, but other plant fibres) filled with a mixture of sand, general purpose compost and vermiculite.
To be honest, because I’d read so many doom and gloom stories about the seeds having low viability, low germination rates and generally being super-tricky to grow, I didn’t hold out too much hope for mine. I put the pots outside, but sheltered by a sheet of glass, and I kept them moist (sometimes I admit they did get a bit dried out, that’s a problem with peat pots).
I was amazed when, after less than two weeks, strong roots started growing through the sides and bottoms of one pot after another. At this stage, there were still no signs of growth on the surface – it was all going on underground. I quickly put each peat pot into a larger plant pot filled with the same compost/sand/vermiculite mix. Within a month of sowing, the cotyledons started to poke their heads out in each pot. The slowest one was about three weeks behind the fastest in making its appearance.
And since then, the little carob trees have been growing on in their pots. Of the eight seeds I sowed, seven germinated and grew to produce true leaves. Of those seven, six are still doing fine; one was pulled from its pot – probably by a bird – and by the time I found it it was quite wilted. That one is still growing, but it is very stunted.
Now that winter is here, I’ve moved the little carob trees (they’re between four and five inches tall) into a cold frame. They’re supposed to be hardy to about -8C (17F) which we’re unlikely to see here, but it’s not impossible. Mainly I’ve put them in the frame to keep their soil dry-ish through the winter.
So, that’s my experience of growing carob from seed: so far, so good:)