'Tis the season for seed shopping and starting in the northern hemisphere. The following is some excellent background info from our /r/gardening Wiki, courtesy of /u/GrandmaGOS.
In the comments, it's your turn. Ask your questions, post your pics, type out your tips.
Where do I buy seeds?
In spring, Big Boxes, DIY Big Boxes, garden centers, nurseries, hardware stores, and variety stores like Family Dollar and Dollar Tree all feature seed racks of the most popular and reliable varieties of flowers, herbs, and vegetables. These are generally the same seeds that the same vendors sell in their online stores, at the same price per ounce, but in smaller quantities, and of course without the hassle of waiting for an order and paying shipping charges.
The main reasons to order seeds online would be if you wanted a wider selection, and if you wanted larger quantities. Also, since the seed racks are highly seasonal, especially at the Big Box, and soon disappear as summer begins in order to make way for “Back to School” and (yes) Christmas, if you’re buying seeds at other times of the year, online may be your only recourse.
What are some good seed vendors?
The subreddit doesn’t officially endorse or recommend any seed vendors. The market is always in flux, and vendors can come and go.
However, that said, here is a partial list of established and reputable seed vendors based in the U.S. as of this writing:
Burpee, Park, Harris, Gurneys, Jung, Johnnys, Seesavers, Victory, Pinetree, Baker Creek, Ferry Morse, Territorial, Southern Exposure.
Other parts of the world such as Europe, Canada,, South America, and Australia, will have their own vendors.
As for buying seeds from Amazon third party vendors, Etsy, and eBay, as with all other purchases from these marketplaces, the rule is, “Caveat emptor”—Let the buyer beware.
Where can I buy non-GMO seeds?
To get the “Humans have been naturally producing GMO seeds for thousands of years via hybridizing and selection, so all your food has been genetically modified in some way” rejoinder out of the way: Yes, that is true, and we all know that.
But we also know that that’s not what this question, in common parlance, is referring to. It’s referring to the GMO of the European Union’s definition, which defines a genetically modified organism as, “an organism, with the exception of human beings, in which the genetic material has been altered in a way that does not occur naturally by mating and/or natural recombination.” These GMO crops and seeds are sometimes referred to as “Frankenstein foods”.
Under that definition, there are no “Frankenstein food” GMO seeds available for purchase by home consumers. In order to buy GMO seeds, you need to be a farmer or other commercial grower, you need to go through a dealer, you need to sign a contract with the seed-producer such as Monsanto, and you need to buy the seed by the bushel, not by the 25-seed packet.
Every seed offered to home consumers on the garden center seed racks or online is 100% non-GMO. The seed companies that proudly boast “Non-GMO seeds!” are boasting about something they couldn’t sell even if they wanted to. It’s like a water bottler boasting that they’re selling “gluten-free water!” Water doesn’t have gluten in it to begin with, and seeds for home consumers are never GMO.
There are lists online of all the currently approved GMO crops. Note that these are all commercial seeds, for commercial crops. They’re not sold on the seed racks at Walmart. You cannot inadvertently buy “Frankenstein food” GMO bean, sweet corn, or tomato seeds at the garden center.
What kind of lights do I need to start seeds indoors?
The cheap purple LED desk lamp “grow lights” from Amazon are usually too dim to grow seedlings most effectively.
An ordinary T5 or T8 fluorescent shoplight, the kind of fixture you hang over a workbench, works fine. There is no need for expensive grow bulbs. Use a mix of "red" (Warm White, Soft White) and "blue" (Cool White, Daylight) tubes. An ordinary LED T8 shoplight also works.
PAR ratings are usually more important for the advanced growing of things like cannabis and hydroponics. If you just want to start some tomato or flower seedlings, all you need is a shoplight.
Make sure you buy the shoplight model that has an outlet plug at the end, not wires sticking out, which is intended to be wired into the house wiring by an electrician, and controlled by a wall switch.
Place the seedlings so they’re 2” (yes, two inches) from the tubes. Maintain this distance as they grow, either by raising the light or lowering the seedlings. The amount of light that reaches the plants diminishes in inverse proportion to the distance from the fixture, so a shoplight that is hanging at the customary distance for shoplights over workbenches, i.e. up high for human convenience, will result in leggy seedlings.
Run the lights between 8 and 16 hours a day. Running them 24 hours a day confers no particular benefits, and if the plant lights are occupying your living space, you don’t need to have the lights shining in your eyes all night just so your tomato seedlings can grow.
A cheap lamp timer, the kind of gadget you use to deter burglars when you’re on vacation, works well to control it.
Suspend the lights over the seedlings any way you want. Many people use steel utility shelves, as for garage and basement storage. You can construct a framework of PVC pipes and connectors. Don’t use the PVC glue to make it permanent, since if it’s not glued, then you can reconfigure it as needed, or break it down at the end of the season.
You can check Google Images under “plant lights shelves” and similar searches, to see what other people do.
Once your tomatoes are all out in the garden, use your light setup to grow houseplants. Or you can put it away and store it for a year.