Growing from seed
Although there are other methods of starting a Lithops collection, growing from seed is by far the least expensive and the most rewarding. Some subspecies can be much more difficult than others but a mixed lot will give you an excellent start with very little disappointment. Apart from seeds, divisions of mature plants and adult plants will give you instant results however they are much more expensive and often very difficult to obtain.
What you need? (apart from seeds of course!)
1. Take-away containers - You can get these at your local take-away restaurant, usually full of good food, or you can buy them new. Get the rectangle ones that are about 60mm deep if you buy them new as Lithops have an extensive, albeit fine, root system off a main tap root......or
2. Pots - Terracotta are the best as they dry out faster. Glazed ones are OK but they do dry out slower than unglazed or terracota pots. Plastic pots are also OK so long as you watch out for over watering and they have the advantage of being light and cheap. A 50 millimeter pot will support a plant for up to 3 years. The ideal size is 65 millmeters as this allows for the long tap root on Lithops. Remember that the smaller the pot, the faster they dry out.
3. Fluorescent light diffuser, frosted Perspex© or plastic - I find fluorescent light diffuser material the best and it’s quite readily available at your closest plastics shop. You can normally get more than you'll ever need straight out of their off-cuts bin for free. Failing that, use any Perspex© or plastic that is not "clear" I.e. it should have a pattern on it so that it is opaque or frosted. This helps to soften the light and distribute it more evenly across the surface. If all else fails, simply use the lid of the take-away container. In any event, don't place the pot in direct sun at all!!
4. Cactus & Succulent potting mix - I have tried several brands of commercial mix. Many of them have lots of organic matter and not enough coarse inorganic material. Amgrow© and Debco© brands are just two that are easy to obtain.
5. Perlite - light, cheap and readily available at all good garden centres and a lot of hardware stores. This is a white expanded volcanic rock and is really useful for opening up a potting mix. You can also use crushed quartz, red brick and any other 5mm or less stone to open up the mix. Don't use crushed limestone or the painted, decorative pebbles found in craft shops.
6. Heat tray - Whilst not absolutely necessary, a heat tray will give you a constant temperature which helps in germination. If you don't have one, you don't need to go out and buy one. You may find that you will have more success planting in late Spring or early Autumn in this case. There are other methods to keep your pots warm but some are not really that safe. I've seen old electric blankets being used wrapped around the outside of a cardboard box. Hmmmm....I wouldn't want to be watering anywhere near that! Of course, if you have a hothouse then a heat tray is almost unnecessary but they will help germination during Winter.
Here's how to get them going:
(A) If your potting mix is not really open or contains a lot of organic material, make a mix of 50% potting mix and 50% Perlite by volume. A quick sift of the potting mix through 5mm mesh will help remove some of the larger organic pieces. "Mouse mesh" from your hardware store works fine for this. You don't have to fill the pot to the top with this mix if you don't want too. I find the Perlite tends to blow/float away a bit if you fill the container with this mix. Generally, fill the pot to leave enough room for a 5mm layer of the sifted commercial potting mix on top.
(B) Fill your take-away container or chosen pot to about 2 centimetres from the top with your mix. If you are using them, make sure you put a number of drainage holes in the bottom of your take-away container for drainage. (Add a thin layer of the straight commercial mix, if you have made a mix of Perlite/commercial mix.
(C) Sprinkle the seeds onto the potting mix surface. Remember these seeds are really tiny so it's very easy to sow them all in one pot! (A light covering of the seeds with a fine, 3mm or less, crushed rock or red brick can be helpful in supporting the young seedlings as they sprout. Don't go overboard, only a very small amount will do) Using a spray bottle, simply wet the potting mix with a fine mist. The seeds will stick to the potting mix particles as they have a coating that is sticky when moistened. Don't use a jet spray, you only want to water them in, not blow them out of the pot!
(D) Place the diffuser/Perspex/plastic on top of the pot or take-away container. The idea is to keep the humidity up. Lithops need high humidity and temperatures around 20 to 30 degrees Celsius to germinate hence...(E)
(E) Place the pot/s onto the heat tray and set the temperature to 25 degrees celcius. If you don't have a heat tray and you are planting in Winter, find a place that stays relatively warm.....(like near a window in the lounge room !) otherwise, put the whole lot into a brightly lit place out of the rain, but definitely not in full sun. (you want to grow them, not steam them!) I find that around 70% shade works well as it's not too bright and the pots don't dry out too quickly.
(F) Keep the pots moist by misting them as they start to dry out. Always put the lids back on to keep the humidity high.
(G) Within about a week you will have lots of tiny Lithops popping up. Some species can take up to 8 weeks so if you are planting a packet of just one species, don't be too quick at throwing them out thinking that they have failed. After germination, keep misting them for another week but leave the lids off for an hour or so each time that you mist them. By the end of the week you can leave the lids off entirely. It takes around 4 weeks before you can leave them go a few days without water but the main trick is not to over water them. Once they are big enough to handle (about 3 to 6 months) you can pot them individually or, if you planted them into the pots you want to continue growing them in, simply leave them to grow on. Lithops can take more water when they are small but will eventually turn to their cycle of growth and rest and it is when they are resting (in Winter) that they are at the biggest risk of drowning.
In Australia, Summer is December, January and February with February averaging as the hottest month. Winter is June, July and August. For those of us that have been around for some time, it may seem that our weather is now running about a month late!