I am just wondering if anyone has success with growing stuff on from the veg section.
For example chitting potatoes, planting garlic using seed from various things?
I am thinking of planting up some garlic that is in my cupboard.
Garlic and potatoes sold in supermarkets are for eating. The ones sold for sale are, in theory, certified as virus free. Up to you to risk planting something that may not produce a decent cro and may infect your soil.
Seeds in supermarket crops are unlikely to come true to the veg or fruit you bought and are also from plants designed to produce uniform crops with a predictable harvest time and shelf life rather than taste.. Seed companies have procedures and systems for controlling pollination to ensure you get the variety on the label.
Seed from specialists, even the big companies, is likely to give you better choice and more flavour if you choose well.
I know that some people do plant shop-bought garlic... however it's not considered advisable as a regular practice as the garlic bought in most supermarkets is likely to have been grown abroad in very different weather and growing conditions ... the garlic sold here in garden centres etc are especially chosen as suitable to grow in the UK and is also certified as free from any plant viruses.
As for potatoes ... again it can be and often is done on a small scale ... however if you want the best chance of getting a reasonable crop for all your efforts you're usually better off getting seed potatoes certified free from virus and suitable for your needs.
I planted shop bought garlic last year, it did really well. I went with it because it's not possible to buy garlic bulbs for planting in the autumn here, however I did buy local and organic bulbs to try to increase the chance of getting something suited to the climate. I have grown shop potatos before and not seen any difference in yield between them and seed potatos. But again it was only to get varieties I cannot buy. I have never tried to grow anything from seed like tomatos or pumpkin, but I have had some volanteeres in the compost heap, they always germinate too late to come to anything however.
I've used Sweet Pepper seed with great success. I get a much better crop than bought seed, stronger plants too.
I agree with Obelixx & Doves points plus certain new varieties are subject to something called plant breeders rights which means you are not supposed to grow them without a licence, though how anyone would check?? On our Allotment we had a Japanese guy try to grow Edamame (Soy) beans without any success at all as he had brought seed from "home". I had great success with it this year but I bought seeds from a UK company that were specially bred for our climate.
I might buy the garlic in that case.
What do you do with potatoes, do you keep some cool over winter to use next year or buy fresh every year? I am just wondering what the nurseries do for their stock?
Supermarket parsley can do well if divided and either potted up or planted out.
Seed potatoes are produced as a crop by specific growers for seed companies. They go o sale in garden centres and so on in early spring or you can order from seed suppliers.
Supermarkets do pots of herbs which can be pricked out and potted on and grown but I would check the prices of plugs in garden centres and nurseries before buying pots of SM herb which are less likely to have had proper feeding, watering and light levels and usually have too much soft, sappy, etiolated growth.
I've successfully grown butternut squash from the seeds from supermarket bought squash for a few years now. Not tried anything else. Must admit in the last few years germination rates for some packet seeds have been really disappointing. Not sure what that's about.