Germination question - Euphorbia, Aloe, Haworthia Rebutia

[esp_imaging]

After some success with a spring sowing, I've done a mid-summer sowing of various plants, partly to learn lessons for next spring. I intend to grow them under lights over the winter.

I sowed on 6th / 7th July, so it's still less than 2 weeks, but I've had widely differing germination rates.
If anyone has insights into the species which haven't emerged, so maybe I could change temperature etc, it would be really helpful.

General growing conditions:
Room temperature, around 20-25 deg C, not much day / night variation
NW facing window, shaded from direct late afternoon sun
Medium - approx 50% mineral cat litter, 35% perlite, 15% comercial cactus compost
Method - microwed medium in small sealing food containers (like takeaway containers but smaller, 50mm x 75mm or so, £2.50 for 5 from Sainsbury!).
No fungicide used. Some threads of fungus abserved from aloe seeds, but zero damping off so far.
Surface sown (most) or only just covered (some Aloes and Haworthias, Euphorbia)

I expect germination to be ongoing, here's the story so far:

Rampant successes:
Lobivia Rossii - 20/34 germinated
Aloe ferox - 21/26 germinated

OK so far:
Echinocereus - 5/10
Stenocactus - 7/25
Rebutia albipectinata - 4/15
Rechsteineria leuchotricha - 8 sprouts, no idea how many sown!

Poor so Far:
Euphorbia tuberculata - 1/21
Haworthia fasciata - 2/34
Aloe tomentosa - 1/30

No shows:
Aloe glauca
Aloe microstigma
Rebutia voilaciflora

So - are the "Poor so Far" and "No shows" just slow and erratic, or do they prefer different conditions? Really hot to get them going?
Cooler (Rebutua viol, Haworthia)? Special treatment - scarify? No light (Haworthia?) I've seen conflicting advice on Euphorbias (hot vs cool) but found nothing specific about E. tuberculata, and various diverse opinions about what to do with Haworthia, again not species-speciific.

Thoughs and advice welcomed! I've kept some seeds back for several species to have another go if needed.

Ed

[Onzuka]

It's all too easy to blame yourself for any lack of success, but do you have any provenance on the seeds?

Steve

[esp_imaging]

A good point, Steve.
All seeds are from the same supplier, obviously they will have sourced them from all over the place.
Aloe ferox and Aloe glauca both have field collection numbers for the same collector, I assume they will have been wild collected, so this suggests very different germination rates (or cultivation requirements) for these 2. Or possibly poor A. glauca seeds..

[greenknight]

Rebutias need cooler temperatures than most cacti, but yours should work.

[iann]

Haworthia are renowned for poor germination. I suspect many people keep them too warm, but even experts say you won't get full germination. Some tips here from someone that knows better than most:
http://www.cocozzacollection.org.uk/haw ... _seeds.htm" onclick="window.open(this.href);return false;

[MrPintxo]

Those haworthia seeds probably need more time.
I sow several cacti/succulent species every year, and this year I've sown haworthias among others for the first time (3 different species), and I've noticed they take longer to start germinating than cacti.
Mine took 3 weeks to start germinating, I was starting to loose faith, but in the end I've had a pretty good germination rate (60%-70%).

[esp_imaging]

Thanks everyone for your reponses.
I may try a further sowing of Rebutia violaciflora when ambient temps are a little cooler. Odd how Reutia albipectinata seem to be sprouting, could be the seed quality of coure, rather than species-specific requirements
Good to have feedback on the Haworthias, I've had one more germinate now. I've also had one more Aloe tomentosa show, so a little more drawn-out action from the Aloeacea, over and above the rampant A. feroxes (which are now even closer to 100% germination).
I get the impression that not too many people grow Euphorbias from seed?

[esp_imaging]

Progress report 2 months in:

Rebutia violaciflora - Last week I finally had my first sprout! It had been cool all week, so I guess it preferred the lower temperatures.
Aloe microstigma and Aloe glauca - still 0% germination. I think both of these were rotting off from fungi on the seed before they can get established.
Aloe tomentosa and Haworthia fasciata - I think these have had the same problem as A. gauca and A. microstigma, mould seemed to develop on the seeds, but I have several surving seedlings from Aloe tomentosa. I've only 1 survivor from 2 Haworthias that germinated, and its growth seems painfully slow compared to the Aloe t.
Aloe ferox has been rampant all along. Very high germination rate and 100 survivors%, many are producing their 3rd leaf now.
Euphorbia tuberculata - only 2 sprouted but they are both strong and vigorous.
Echinocereus rigidissimus v. rubispinus - good germination and now growing strongly
Rebutia albipectinata - good germination and now growing strongly
Lobivia rossii - good germination and now growing strongly
Stenocactus - OK germination, some growing strongly
Rechsteineria leuchotricha - doing well, 2-3mm caudices forming on some of the plants. They were so tiny (<1mm) when they sprouted!

All the seedlings are still in sealed tupperware containers, except for some aloes and haworthias, which seemed to be rotting in the sealed containers, and the 2 Euphorbias which I tranplanted as the quickly outgrew their headroom.
Most of the cacti are on a a heating mat in NW facing window which gets a little evening sun, most of the succulents are in a window which gets some direct midday sun - possible overheating in the sealed containers doesn't seem to have been a problem this year.

I kept some seeds of R. violaciiflora, Aloe glauca and A. microstigma. I have just done a sowing of all 3 which I will keep cooler. I experimented with pre treating the Aloe seeds with bleach or H2O2 or a hot water bath. I washed the Rebutia seeds briefly in 3% H202. In the next week I will try various pre treatment of the remaining Aloe seeds, and sow in warm conditions.

[Astro]

I also tried some Aloe seeds this spring, with results pretty similar to yours. Pretty much the only thing that sprouted was A. ferox, and sprout it did! But other than a pot full of ferox, I have nothing to show for it (I tried plicatilis, castanea, marlothii, dichotoma, petricola). It does raise some questions about the age of the seeds (in my limited understanding Aloe and Haworthia seeds lose viability over the course of one or two ears, so best not to wait too long before sowing). On the other hand, maybe A. ferox is just super accommodating or all other species equally disliked the offered germination conditions.

I did try A. petricola (and 2 Haworthias) from another source and all those germinated promptly (for smallish values of 'promptly' for the Haworthias, but still ~50%) under the same conditions.

Having said all that, when acquiring Aloe or Haworthia seeds I currently accept it is a roll of the dice if I don't know the details about the seeds' age. Lithops are quite a bit more forgiving in that respect, seed stays viable for ages.

[esp_imaging]

Update, over 3 months in:
A) 2 or 3 R. violaciflora have now sprouted. A spell of <20deg C temps may have helped.
B) Yesterday, the 3rd E. tuberculata finally sprouted! A long wait, erratic progress!