As for some things I've learned this year, in no particular order.
Slugs love Lewisia and Aloe seedlings. Use Sluggo or you'll be left with nubs time and time again.
Anyone trying to germinate South African plants like Protea, Slugs love the dicots but not the mature leaves. Protect them from early onslaught. Protea and Lecuadendron are easy to germinate. Here are those that I had 70% germination or higher: Pr compacta, cynaroides, lacticolor, repens, subvestita (near 100%), Ld salignum, sessile, microcephalum (first up). Ls are the harder ones. Ls concocarpodendron and glabrum are the easiest for me. For all my SA seeds I used a mix of 3 parts quarter minus gravel, 2 parts perlite, 2 parts pumice, 2 parts orchid bark, 1 part Turface MVP. Drains instantly, very very few fines, but good water retention even on hot days. The flats are HEAVY though! Protea seeds were sown 2 per pot in 2.5inX2.5inX6in square pots.
Sow Protea after there will be no more 80F+ days. You will lose a lot to rot before they ever come up if it's too warm. Temperatures in the 40's at night really signal germination well, so that's October in Portland. Protea germinate within 6-10wks. After that, the ungerminated seeds are usually rotten. Hard Shell Leucadendron and Leucospermum seeds can sometimes be viable for 12+ months, but usually have come up or not by 3 months.
I was forced to trying to grow a few Protea seedlings indoors (with very little light and air movement) and I lost a good half of them due to rot. I had them in the bright airy sunroom the next year and lost none. If they must be indoors, keep a fan on during the day and don't overwater!
SA Erica are really hard to germinate! E speciosa came up after 4 months... The others were sporadic at best.
There are two kinds of Leucadendron seeds: Flakes and nuts. The smaller ones are flakes. The fastest growing Ld is argenteum, but Ld argenteum takes minimum 2mo to germinate.
Proteas only branch 6 inches or so from where you prune and they don't back bud past where there are green leaves. Keep this in mind if you want low branching! I pinched all my seedlings at about 6-9 inches this year in hopes of a denser bush next year. They grow to be 2 ft tall after 2 years and 2nd year plants fit into a 1gal pot (3rd year in a 2 gal). Pr repens branches freely without pinching, usually, as do Lignotuberous species like cynaroides.
The easiest SA bulb genus for me was Babiana. Other SA bulbs are smaller and slower, but germinate well once the cold temps actually come in December thru February. Fertilize lightly to grow nice sized bulbs. The hardest ones are, as always, the diminutive species like Geissorhiza corrugata with its awesome spiral leaves.
If you run across some seeds of Dicentra formosana ssp oregana...
...and you wish to propagate this beautiful species, here's how: Black shiny seeds dehisce about June 1. Collect and soak seeds for 24hrs in water. Attached to the seed is a tiny fleshy white root looking thing whose name I forget. I didn't want to damage this so I didn't manually scarify the seeds. Drain and put seeds in a plastic bag of peat/perlite in the fridge. I stored at 3-5C for 2.5 months and sowed on the same mix of peat and perlite (plus pumice for extra drainage). The seeds were already germinating in the bag after 2.5 months. I put a tiny amount of soil over them. Less than 2wks later, I have a good % coming up. I also tried storing dry cold, sowing immediately in June, and storing frozen. None of these have germinated yet, but may eventually. The first method described is obviously adequately satisfactory.
2009-10-11 Update: The Dicentra seedlings germinated at about 50% as described above. No seeds from the other treatments have germinated yet. Do NOT transplant the seedlings right after germination. I transplanted 15 plants at various stages at about 1mo after germination and 12 died. The 4 that I didn't transplant survived.
2010-02-21 Update: The Dicentra from the other treatments germinated well this Spring. They're just 5 months smaller than the others.
