I wrote a post yesterday about artichokes, and mentioned that you could start them from seed or cut off the suckers and root those as new plants. Commercial growers have relied almost completely on suckers because they could count on plants from those off shoots as being exactly like the parent plant. Plants grown from seed were less reliable. We have had Violetto plants grown from seed that looked more like wild thistles than artichokes, though that outcome has been rare. I am a home gardener, not a botanist, so I speak from experience only - and I can tell you that artichokes grown from seed have become much more consistent in appearance and production over the years that I have been starting artichokes from seed. I am told that more commercial growers are starting new plants from seed than ever before because the seed starts are more reliable and it is far less labor intensive to start plants from seed than from side shoots.
We have a system and most all of our seedlings are started the same way. We use 200 cell plug trays in 10 X 20 inch trays. We plant the seed into the tray by hand and, depending on the seed, either on the surface, slightly below the surface, or deep to 1/4 inch. The trays are then set on warmed shelves to 78 degrees, kept moist, and protected from cats (see photo of seedlings behind bars) and mice (who love to eat the new tender leaves). Once they have germinated and have a good set of cotyledons (primitive leaves, replaced soon by true leaves), the trays are moved to cooler levels of shelving. All seedlings receive 14 hours of fluorescent light each day. When two sets of true leaves appear, the seedling tray is moved into the greenhouse where the plants will be potted up into 3" containers and set on warming tables which keeps the nighttime temperature above 50 degrees. Daytime temperatures, even in this dreary January/February climate, may reach 80 degrees and the light is far better than the fluorescent light they experienced as seedlings.
Some plants just can't be started from seed and some can, but barely.
Those that cannot be started from seed include French Tarragon. Those we start from root divisions in spring. French Tarragon is a sterile plant that does not create seed. African Blue Basil is another sterile plant that cannot be started from seed, but is easily started from stem cuttings. Lemon Verbena develops tiny seed but is started more easily from stem cuttings. Stevia is a plant that flowers frequently and develops fertile seed, but the seed has a short life span. Rather than taking a chance on seed that may be too old to germinate, it is more reliable to take cuttings. Scented Geraniums are propagated easily from stem cuttings that are clones of the parent plant.
I still make mistakes, even though I have been doing this for many years. I started a plug tray of three types of plants, neglecting to notice that one of them required light to germinate. That meant the seeds should have been set lightly upon the top of the soil, and only slightly tamped down. I buried them to 1/4 inch and wondered why they didn't germinate - then I reread the seed packet and realized what I had done. I replanted them with great success.
The moral of this story - celebrate the variation of seed requirements for germination. Read the seed packets for the unique requirements of these seed: Do they need light? What temperature is best for germination? Do they need total darkness? Do they need to be chilled before they are planted? Do they need to be scraped with a knife to open the seed shell? Some seeds love to be soaked in water for a day.
It's a challenge and a thrill to see seeds emerge and then quickly take on the characteristic of the lovely plant they will soon become. Enjoy the experience.