When do you sow your seed?

[Brian]

Having received my BCSS seed very promptly - a big thank you to the folk doing this - it got me wondering.

When do Forum members get sowing? Anybody already done this? If so, have you done so under artificial light?

[Herts Mike]

Last week of Feb. Not under lights.

Unless winter growing e.g. Pelargoniums when I sow in September.

[Peter]

Did mine yesterday. I have clear plastic boxes with 24 compartments and after sowing the seeds I leave them against a warm wall in my study. When signs of life are apparent the boxes go onto a window ledge.

[DaveW]

When you can provide the right conditions of heat and light. Artificial provision of heat and light is only really necessary if you want to sow seed out of your countries normal growing season. This is often done with slow growing plants like Cacti & Succulents in order to obtain maximum growth before winter.

You can in fact just sow them in the greenhouse in the growing season (Spring onwards) just under the stagings without any additional heat or light, just as you would do for bedding plants. Fluctuating day and night temperatures are not a problem at that time of year and may even help germination.

This table originally off the Web, was the results of various germination temperature results.

[AimeeHoward]

I completely agree it is very essential to provide (even if in artificial way) light and heat to the Cacti if you really want them to grow well. But first of all you will need high-drainage soil to plant the seeds, then regular watering. It would also help if you cover the pot with a transparent lid (like plastic wrap). I have been part of a company which provides variety of gardening services and I am pretty sure of my statements.
Regards,
Aimee

[rodsmith]

Mid to late February has always produced good germination for me.

[Benjy]

I always sow the end of December with heat and artificial lights,
then around mid/late March I remove the bags and all the pots and trays are moved to my greenhouse,
either on the floor or under the benches, out of direct sunlight until they toughen up.

After 12 Weeks

[Aiko]

For the Mesemb Study Group bulltin I had written an article on when I do my sowing. Here is a draft version (for now I can't get to the final version) of the article that was published.

For some cultivating activities it is best to watch the weather. For example, when to decide if you will water your mesembs, or how much you will water them. Or to decide if you want to increase or decrease the ventilation in your greenhouse. For other cultivating activities it will be best to just watch the calendar and don't bother too much with the weather at the time. For me, sowing is one of those activities that I do based on the time of the year instead of how the weather is. I think most readers will agree the right temperature is key for germination. As the process of germination runs over multiple weeks, it will be a bit tricky to assess the coming weeks if they allow for perfect germination temperatures. On the whole, the weather on a certain time of the year will be the same every year. Sure some days or nights will be much colder than you will wish, on other times they will be warmer than you will like. The basic circumstances spanning multiple weeks in a certain month will be the same every year, and seeds you have sown would have had enough chances to experience their ideal sowing temperatures. So it would be best to just watch the calender to decide when to sow.

I do al my sowing in an unheated greenhouse. My climate up here in the Northwestern Europe is quite moderate. No scorching hot summers, and no Siberian winters. What we have all year round is wind. But that is of not much influence to a germination process as long as it is not knocking out panes from my greenhouse. There are days with a lot of sun, alternated by dull days. I don't use any artificial light. And both at night and during the day I keep multiple windows open for ventilation. Of course this allows for less control, but I don't mind the occasional challenge. I could probably have better results if I use heath mats, artificial light, thermostats and all of that. But I am not liking the idea of a fire hazard running for hours during the day when I am not home. So I just keep things natural. At least as natural as cultivating in a greenhouse can be called. During early spring at night, the greenhouse could be rather chilly. But during the day the greenhouse will warm up rather fast as soon as the sun shows itself. The difference in night and daytime temperatures are supposed to be beneficial for the germination process of mesembs.

For me, there are three distinct moments when I do my sowing:

1 The first distinct moment will be in the second half of March. This is the time when I sow African succulents that have a preference for low but frost free temperatures. This could be winter active succulents such as Conophytum, Mitrophyllum, Monilaria, but also species like Tylecodon, Bulbine and Massonia. Also mesembs that prefer to grow during the summer such as Pleiospilos, Lithops, Faucaria will be sown in the second half of March, together with species like Anacampseros and Haworthia that also like chilly nights.

2 The second distinct moment will be the second half of April. This is the time when I sow all of the cactus species. But also African succulents that prefer nights being less chilly, such as Pseudolithos, Pachypodium and Adenium. Basically all caudiciform African succulents. The nights still aren't warm, but not as chilly as one month earlier. During the day the temperatures inside the greenhouse could be rather high already, thanks to the increased sun intensity and lengthened hours of sunlight. The difference in temperature between day and nights are about as large as one month earlier. But as the minimum temperatures at night and the maximum temperatures during the day are both higher, the difference between the two are about the same. It is just the average temperature that has increased. This should be more beneficial for all cacti and warmth-loving African succulents. In general I don't sow any mesembs at all during this second distinct moment. I think they might still germinate well enough, but fear the very tiny seedlings will not grow well enough in the warmth.

3 The third distinct moment will be the second half of August. This is a moment for winter active succulents only. In practice this is the time I only sow just a few species, though. Firstly, this is the time to sow any winter active succulent I only obtained after the first distinct moment in March. And secondly, this is the time to sow the very extreme winter active species. For me the latter only concerns Diplosoma (Maughaniella). In late August the nights will still be relatively warm, and even during the day it could still be hot. But as the span for germination takes a few weeks, by the time the seeds are about to germinate and grow as a seedling it will be September already. At that time the nights are getting noticeably colder and colder already. And during the day there still is much sunlight without being too intense for freshly germinated seedlings. This results in very fine growing circumstances for those species that remain active during the colder days of the year.

Winter active succulents in general go dormant when summer is approaching. But when sown in spring, they do continue to grow through their first summer. Some species don't go dormant at all, other just for a very brief moment. It is not until next year in their second summer when the seedlings go dormant all summer. This goes for almost all species. The only exception to this from my experience is the genus Diplosoma, both Diplosoma luckhoffii and D. retroversum. These are extreme winter active growers! As soon as the heath of late spring arrives, the leave pairs die off and whatever remains of the plant is hiding underneath a layer of dried sheets. In contrary to other winter active mesembs that continue to be active in their first summer, this also happens for Diplosoma seedlings sown in early spring. At that time they are simply still too small to survive a dormancy. Diplosoma will go dormant when the heath comes. There is no stopping them. Even when they are just very tiny they will go dormant, but never will wake up again in the autumn. But when sown in August and germinating in the cooler September month, the seedlings will have more months to grow and build up some mass to survive the long summer dormancy. I have tried growing Diplosoma a few times, and only have had success getting them past their first birthday if sown in the autumn.

Second chances
There are always some pots with seeds that do not germinate. This could be due to seeds being too old. You can't do much about that. In case the seeds are too fresh, you could give them some more time to mature and give them a second chance.

The seeds of winter active succulents that don't germinate during the first distinct moment, I will allow them a second chance in the third distinct moment. If the seeds that have been sown at the first distinct moment in late March sill haven't germinate after two months, I will not give up on them just yet. I will simply allow the pots to dry out completely, and store the pots in the greenhouse somewhere in the shade, hidden under the tables. By the time it is August and the third distinct moment has arrived, I will soak the pots again and just patiently see what happens. It is not uncommon for some seeds to germinate after all. Especially with Dinteranthus vanzylii I have experienced very good results in its second chance. I have had multiple experiences with D. vanzylii to show near 100% germination results in their second chance. But this is an exception, I must admit. Usually a second chance only results in a much lower rate of success than any first attempt would have showed. But that is still better than not success at all...! In case a second chance is not successful after two months by the time it is October, I will simply allow the pots to dry out again. The pots will be kept in the greenhouse, and stored under the tables in the shade again. Their second chance is set again for next late Mach again, along with the first timers of that year. My expectations will be lower for their third chance.

In case I have given up on a pot to germinate, I don't just throw away the still perfectly fine soil, but re-use it for plants that need to be repotted. Even after a few years the odd seedling can still germinate. I have an Argyroderma plant potted up in some re-used soil. Next to it I suddenly noticed a leave of a Massonia growing. I sure haven't planted it there deliberately. Apparently one seed ended up in the right place in the pot, and germinated after I had given the Argyroderma some water sometime during 2014, years later after its first chance in (I assume) 2011.

The summer active succulents that I have sown during the second distinct moment that have not shown any germination after two months, only get their second chance next April, one year later along with the first timers of that year.

Keeping the pots with the non-germinated seeds in the greenhouse should have its advantages. The seeds in pots that are kept in the greenhouse during the summer, have to endure the heath of summer. This might help to induce the seeds to germinate in the autumn, during the third distinct moment for sowing. I think this might be beneficial especially for mesembs, such as Dinteranthus vanzylii. Old age is usually not a big problem for mesemb seed. Seeds could germinate perfectly even after ten years or more. Especially if stored in their capsules. I reckon if there is a problem with mesemb seeds, seeds being too fresh might more likely be the culprit. And those seeds in pots that are kept in the greenhouse during the winter, have to endure frosts. If the summer heath doesn't help the seeds to germinate, maybe frosts might do the trick? I am sure it will definitely not hurt the seeds as long as they stay dry.

In case the results of the second and third chances are no success, you could always decide on allowing them a fourth, fifth or sixth chance if you still feel confident. Although I would not hold my breath for it by that time. But you never know, plants could surprise you!

[esp]

I've sown small quantities at pretty much any time of theyear, during hte cooler months I rely on a £27 LED grow light, plus and a little more-or-less year round bottom warmth.
With a simple light / heat set up, I can't see any benefit in waiting. If you have hundreds opackets to sow and can't provide a decent area of artificial heat and light, I'd guess you go for as early as possible in the year as you can get away with, with sufficient warmth.

[Chris L]

I always sow mine mid-February to mid-March, in bags, inside on an south-east facing bedroom windowsill.

There is a radiator under the window too.

My attempts to germinate seeds in the greenhouse haven't turned out at all well.