The technique is perfect greenhouse conditions, perfect temperatures and light, excellent soil and drainage, just right humidity, maximum fertilizer just under the amount that would kill the plant, and growers with years of experience, enough money and lots of time and patience. That packed pot on sale today will need to be transplanted soon because its roots are pot bound. It will be replaced if it ever looks bad. Plants are living things that need to go through cycles of growth and rest, blooming and recharging. If you really want to grow plants that look fantastic, you need to devote yourself to learning how to do it. It takes time and dedication just like anything else in life that is worth doing. Explore this forum, ask questions and search for answers. There are people here who can grow plants like that. Be humble and learn from those who know.

Some of us like to learn how to do things in more efficient, controllable, repeatable ways. It wasn't some kind of ordeal for me to learn how to do things properly--it was great fun. If you're the kind of person who gets joy out of growing mystery unstablized tomatoes from your compost scraps and don't mind taking the risks that come with not fermenting seed, then all power to you--whatever gives you joy. But don't make it out as though experienced people on here who try to teach others best practices and point out realities such as the fact that you might get a dud from the offspring of a hybrid commercial tomato or that some varieties don't do well in some places or that tomatoes need time and care to produce *optimally* are sucking the joy out of anything for anyone. They're just trying to give people a way to maximize their harvests, avoid diseases, and avoid unwanted genetic surprises in their tomatoes. People are free to learn from their advice or not--nobody is sending in stormtroopers to arrest them for using compost to start plants. I don't always follow everyone's advice here, but I do appreciate that they take the time to give it.

In the right climate and with the right conditions, grocery store or "florist hydrangeas" can be transitioned into the landscape without issues. And yes, they will bloom again, provided all the factors that affect hydrangea blooming - like winter and late spring cold, poor pruning practices, etc. - are correctly addressed. They do need a transition period that will gradually acclimate them from indoor conditions to outdoors and not acknowledging that could impact how well they may do. It might account for why yours seemed to head downhill after being planted outside. Sometimes it takes several season before the internal calendar of the plant gets back in sync and it flowers on schedule. And you do need to be aware of those other previously mentioned factors that can impede or eliminate flowering. But they most definitely can adapt to the outdoor landscape and bloom successfully. And live for many years.

Ginger and turmeric roots will also grow. I've not tried turmeric yet, but have best success with an organically grown ginger root that has just a few greenish looking nubs that show promise of becoming buds and new growth. These are tropical, so something I have to plant in pots to bring indoors in winter, but in your Zone 9 climate, they should be happy year 'round. Any part of a horseradish root will grow ... vigorously. The bottom of a bunch of celery will regrow, but I've never tried growing it for long, so don't know whether it would eventually produce something harvestable/usable. I've grown garlic from supermarket garlic, but all things considered, don't mind paying the higher price for heirloom garlics, especially the hardneck varieties. 1. Grocery store garlic is usually a softneck variety, as it has a longer shelf life, and may have been grown anywhere in the U.S. or even in China; 2. Hardneck garlics are said to have more of the healthful substances for which garlic is known; 3. I buy from local, organic growers, so I know the planting stock is well-suited to growing conditions in my garden; 4. There are so many wonderful varieties of garlic out there, with different top notes and finishes! Mild, strong, hot, spicy ... different kinds suited for all kinds of cooking: French, Italian, German, Spanish, South American, Asian, Cajun, etc. (Not that I grow them all.) 5. The return on investment is pretty good. Since each clove will grow a whole new bulb, you can get anywhere from 6-12 new bulbs from each single bulb you buy. Another nice thing about the garlic is that it's best planted (here in Zone 7) in the fall, when gardens are usually "put to bed" for the season. It's 28 degrees out there and my garlic, which has already sent up shoots, is fine, and will be throughout the winter, which can get down to the teens and even single digits occasionally. It will have a few growth spurts during milder spells, then growth will really take off in early spring, scapes will be harvested in mid-spring, then the bulbs in late May or early to mid-June, depending on our weather.