Sunday, September 30, 2018

Lithops cultivation on a windowsill (16 pics)

Recently I realized that after almost 10 years of writing about growing lithops and other succulents under less than ideal windowsill conditions I do not have a single post here that would summarize the whole endeavor. Let me try writing it all down now and if I miss something comments are always appreciated :)

Full disclosure. My approach is not scientific, I do not know the pH of the substrate nor do I note the average air temperature throughout the year. The experience I've gathered is based on close observation of the plants and learning from my mistakes. 

1. The windowsill

There are some things you need to know about my windowsill: 

- It is quite spacious, measuring 0.6 x 2.5 meters. Currently I have 4 trays of plants there with several pots standing free. There is room for the 5th tray but I like to have some free space as I do my sowing and repotting (and my cat does her sleeping) there as well. The trays are 40x60cm and contain 77 containers each. I also use the spaces in between trays for shallower pots with younger seedlings and such.
- It has window panes on 3 sides, not just one, thus allows just a little bit more sunlight in during the day. The longest period of full sun exposure is between 6 am and 2 pm in Summer, which is not nearly enough. It's much much less than that in Winter (if the sun comes out at all). There are spots on the windowsill, behind the non-glass parts of the windows, that have more shade. I use those as well, in rotation, for example for sleeping conophytums or rooting adromischus leaves. No free spot stays unused.
- It is directed somewhat South-East, I believe. Meaning, when the sun rises it first appears straight and slightly to the left. Bear with me, I'm really not a scientist.
- I do not use any artificial light. The light the plants get solely depends on the weather.
- I do not use any fans, nor open the windows. The windowsill is in my living room, separated from it by Florentine tulle. Whatever air circulation happens naturally (probably caused by me running around) it seems to be enough.
- I do not manipulate the temperature in any way. In Winter it has about the temperature of my living room (I do not heat during the day when I'm at work). In Summer the temperature rises up to 48°C when the black pots get too hot to be touched. There was never any sunburn related damage on the plants that I can recall, probably because the sun moves on from the windowsill by 2 pm.

As you can see, the above describes the general conditions, constant value, on which I have no influence.

So what are the points that we actually can manipulate? What is it we can do to compensate for all the unforeseen weather-related hardships of our lithops and help them be their best selves?

Here comes the No 1 Rule for growing lithops on a windowsill: Keep your plants as small and flat to the ground as possible. Your goal is - by all means necessary - to prevent them from growing upwards, also known as stretching. The slower they grow and the smaller they stay the healthier and prettier they will be and the longer they will live. All the care you give them should have this as a goal. You can achieve it by controlling what substrate and pots the plants grow in and by restrained watering. 

2. Substrate and containers

The substrate I use is pure pumice or pumice sand. There is absolutely no compost in there nor perlite or aquarium gravel. The size is often referred to as 0-2 mm but what it is is small pumice stones with pumice sand. Both Kakteen-Haage and Cono's Paradise sell it, if you're in Germany/EU, but it is also available on eBay or in stores specialized on bonsai. I tried Akadama, by the way, and it was a bad idea (the stuff they sell here is full of chemicals and slime). Do not use lava stones with holes in them for decoration either or you will never get rid of mealy bugs that hide in there. And if you use decorative quartz as top layer you will not be able to know whether your plant already has been watered recently or not and will keep watering it unnecessarily (believe me I know). In short, it's all pumice, all the way. Below is how slightly moist pumice looks like straight from the bag. I do not wash or microwave it. I only microwave the pumice I use for sowing (650 watts/1 kg/3 min).

You know how lithops like to rot? In pumice it rarely happens. The way it works so well is that the plants don't get "wet feet". Pumice does not retain moisture in a way compost does, making a swamp. Wet pumice, while sucking in water, does not let the roots actually be "in the water". The roots are semi-dry (no swamp) while the plant can still pull the moisture out of the stones when needed. This not only prevents rot but also is a safeguard against overwatering because it dries quicker. One wrong watering (that's often all it takes for your plants to start stretching) in pumice is less likely to be as dramatic as in other substrate. I refresh the substrate every 3 years or so.
It is also important that when you buy a plant that's already in a pot, you immediately pull it out, wash it, let it dry and transplant it into dry pumice where it will stay unwatered for at least a week. Even if you buy a plant from a specialized nursery and think that they use appropriate substrate and want to keep it - don't. What works in a greenhouse will not work on a windowsill. Any trace of plant food or compost will lead to stretching when there's not enough light to support the boost of growth (see No 1 Rule). 

For adult lithops plants I use square plastic containers (with drain holes of course) that measure 5x5x8.5 cm. Anytime I tried something bigger I lost the plants to overwatering. You have no control in bigger pots. 5x5x5 cm pots would work very well, too. Lithops roots go deep though and the depth of 8.5 cm seems to be good for them. Kakteen Haage and Kakteen Schwarz (wholesale) in Germany offer them. The main thing is that the pots are small and you squeeze as many plants (of the same species and age/size) in one pot as possible without them touching each other. One-plant-per-pot approach is for greenhouses.

It is not only space-saving but also another overwatering safeguard. What one sleepy lithops cannot drink up, its neighbor will; what one greedy lithops could have consumed all by itself, it now has to share with others - no rotting roots and no stretching. Normally I have 4 one-headed plants in one pot or 2 two-headed. Below are 4 two-headed plants happily living in a 5cm pot. I can squeeze up to 16 seedlings into those 5 square centimeters - it only does them good.
Also, use plastic, not clay. It dries quicker, is lighter and transplanting is much easier - just squeeze and pull. Thank me later.

3. Watering

This is the most tricky part. And the most important. You will have to summon all your power of observation and self-control to figure it out. Here are some pointers.

The first thing to remember is that once a year lithops need to change their leaves. The regeneration is a long process that takes several months to complete and during which old leaves completely dry up while the new leaves feed of them, recycling all the moisture. Unfortunately lithops are opportunistic and don't know what's good for them. If water keeps coming old leaves will never dry up and then stacking begins. At the end the new leaves choke on the old ones and the plant stretches, rots and dies. So much for the background.
Our task is now to support the regeneration. In northern hemisphere it means to stop watering completely mid- or late October. The last splash of water comes with a wilting flower. Once you stop watering the roots will become inactive and the old lithops leaves will get wrinklier and wrinklier. This is exactly what we want to see. Winter is a period of active growth, in fact - underneath, deep inside the plant, the new leaves are growing. The wrinklier the old leaves, the bigger the new ones. Around April the old leaves will be gone and the new fresh leaves will emerge. It can be earlier, it can be a bit later. This indicates that you can start watering again. If the old leaves are digested earlier it's better not to start watering until the weather stabilizes (many consequent sunny days). If the old leaves are not fully digested until June, cut off what's left of them and pretend they are. The roots will quickly re-grow and the plant will react to water after the second watering at the latest.

The second thing to remember is that between April and October you can not water by schedule. There is no schedule like "water all your lithops every two weeks". Now your power of observation comes into play. You look at every each of them, one by one, and decide which one gets watered and which one doesn't. Just looking is not enough, you also have to touch them. If they are wrinkly and soft (sometimes even hiding in the stones) - you may water. Otherwise you may not. When in doubt - don't water, re-evaluate in a week. Sometime during a Summer heatwave you might notice that the plants are wrinkly but hard as a stone. They are resting and no water is needed then. This is supposed to encourage flowering but who knows. Flowers on the windowsill are an exception, not a rule.

How much water do I give them? To illustrate, this is the watering can I use. For watering of one pot, no matter how many plants are in it, I use half of it.

I do not fertilize. Because I always forget. When I do remember, I do it in August or September. The beginning of the year feels too risky (stretching).

4. Sowing and seedlings

You guessed it, I use the same place and the same substrate for sowing. All my plants live together on the windowsill, including newly hatched seedlings. The difference is that I microwave the pumice before sowing and use 4x4x4 cm small pots (mainly because 20 of them neatly fit into my mini hatchery, formerly known as "jewelry box"). Bigger Ferrero Rocher boxes work well for sowing, too.

The method is simple: label the pots, fill them with pumice, make it wet, spread seeds on top, cover with a transparent lid and wait. No artificial light needed. You should sow either in February or in September though, when it's colder. In my experience germination starts one week later. Sometimes I get new seedlings after one month. Don't get discouraged. The "3 days" info you find online is fairly unrealistic. For the first few months the pumice surface should stay moist at all times. It does not mean you need to spray every hour. It stays moist automatically because the lid is on. Keep the seedlings under the lid until you feel they are strong enough to move out or be transplanted. Wait until the first true leaves to be on the safe side (about 4 months).

You will see a significant change in their surface structure after the first leaf change. It will be much firmer and stronger, it might already have some color that will keep them safe from strong sunlight.  It's safe to remove the lid and let the pumice surface dry between waterings now. From there the care is basically: when you see them shrivel a bit, give them water, all through the year, even in winter. They are not on the yearly leaf changing schedule yet and will regenerate whenever they like, several times a year. It's how they grow.

This is how they will look like after 2 years. Yes, if they are at this size (4 mm?) you're doing it right. After two years they should be close to the yearly lithops life cycle and at the age of 4 they should start looking like adult plants. Do not believe the info online that they will flower when they are 3 years old. Can you imagine these tiny kids flowering? In a year they won't be much bigger.

Be patient. This year the seedlings I grew from seed 10 years ago are flowering for the very first time. And oh how rewarding this is!

Wednesday, August 15, 2018

Avonia flowering (22 pics)

It's that time of the year again! No, not the cherry blossoms time. It's Avonia quinaria time!

But before we get to that, there's more Avonia news I'm probably even more excited about. This year, for the first time, I was able to catch the worm-like Avonias flowering, too. I was convinced they would never open their flowers under my growing conditions, producing seed pods out of flower buds directly. I don't know what happened but this year I could witness the actual flowers. Maybe I was not paying enough attention before (I thought I did!) or maybe this time the heat wave was bringing my windowsill closer to the growing conditions of a greenhouse. Or maybe now that I have more Avonia plants the chances of catching one blooming are higher. Also, while Avonia quinaria open their flowers around 6pm, other Avonias seem to open them around 2pm or 3pm, reducing my chances of seeing them further. Luckily I was on holidays :)

My old Avonia albissima ssp. multiramosa apparently has small, greenish flowers. Good to know. In all those years I'm seeing them for the first time.

This other Avonia albissima has rather large and showy flowers. The fact that the sun is shining on these flowers means they opened before 2pm. 

Avonia grisea (Av133). Very delicate.

Avonia papyracea. The round white petals look like scales. No wonder the flowers are difficult to spot. Especially if they are facing the light source and not the beholder.

Now to the quinarias. Their flowering is always an event! 

The two of the pink-flowering Avonia quinaria ssp. quinaria plants have flowered a while ago, of course not at the same time, that would be too nice of them. And even now I have one pink plant growing flowers. So much for synchronized flowering.

One of them is producing flower with different number of petals within the same flowering season. It's been doing that last year as well. But hey, I've had Avonia quinaria flowers with 4 petals before, too. The regular number is 5. 

I could still get some seeds out of them. While passive self-pollination is very unlikely, I find that brush-assisted self-pollination leads to seed pods more often than you'd think. I even have one seedling to show for it. It's not the only one that germinated but the only one left. I'm not that good at this yet. But seeds produced by selfing are definitely viable.

Speaking of abnormalities. I have this really strong and healthy white-flowering Avonia quinaria ssp. alstonii. It has grown all those branches and I was expecting it to flower nicely. Weeks go by - nothing happens, no buds. You see, normally, the buds would grow from the tips of the branches and then those branches would fall off. Just when I thought there will not be any white flowers this year, the plant started growing buds from its stem! Well, not  from the stem, but from the new and very short branches it grew just so that it can grow flowers. For some reason it wanted to keep all the long branches and that's kinda clever. Why grow long branches for flowers just to drop them off afterwards? That would be wasteful. Better to quickly grow something short instead. Well, it grew 11 flowers in the end and I got my white flowers after all.

And here's another strange thing - one flower opened completely without anthers.

I tried to take some artistic photos, with a proper background. Too bad I didn't have anything black :)

Sunday, August 5, 2018

Adromischus propagation (13 pics)

It's not easy to find information on Adromischus propagation in general. Actually, there is basically no information at all. These days I have been trying to figure it out on my own.

I have to say, propagation by leaf cuttings is rather straightforward. Even a complete newbie like me can successfully get backup copy plants by sticking leaves into pumice. It is recommended to leave the substrate with leaf cuttings dry, however, I do water it a little. It's risky and so far I have lost one healthy leaf to rot but I think roots come out quicker this way. So if you follow my example, do it at your own risk. Roots normally come after a couple of weeks already. For leaves you might have to wait much longer. Once the new leaves come you're on the safe side.

If you want to propagate your plant it is better to take a bigger healthier leaf. I know, you don't want to ruin the looks of the mother plant (those leaves grow very slowly) and would probably take an older uglier leaf from the bottom. That's no problem. Just don't wait too long, not until it gets shriveled and spotty. It still has to be firm, big and fresh and full of water (water the plant several days before snipping off the leaf if necessary) to give the new plant a better start. The new plant will feed of this leaf for up to one year. The bigger that first leaf the quicker the new plant will grow.

So here are some of this year's cuttings.

These are the leaves of an Adromischus marianiae "Little Spheroid" plant that arrived in spare parts in April. After approximately 4 months there are now new leaves showing. But make no mistake, these are only 5 out of the 14 leaves planted. All the rest of them don't show any new growth at all, although they have grown massive root systems.

As you can see, the roots are very well developed and the plant makes sure to grow all this bulk before it starts growing leaves.

Here is a leaf cutting from another "Little Spheroid" plant. The initial leaf was bigger and, even though it was planted later than those kids above, the resulting plant is much stronger and much further along.

Here are the 4 Adromischus marianiae v. herrei "Lime Drops" leaves I planted back in April.

This one seems not to recognize gravity as a growing guide. It's all over the place. Roots grow upwards, leaves grow downwards. I didn't even know how to plant it best. Maybe I should have cut off one of the roots and planted it sideways. 

This Adromischus marianae v. herrei Alveolatus, Kinderle was planted end of May and has just started growing new leaves.

They are all so small at the moment. It's hard to imagine they will look like their mother plants at some point. But the growth spurt will come eventually. Below is a plant I grew from a leaf only last year. After 1,5 years it looks like a perfect adult plant.

I plan to write about Adromischus propagation by seed soon, too. Or rather the pollination part of it. Growing them from seed is not particularly difficult but you need to be very patient. Below are 15 months old seedlings. They still look like nothing. Cute though.