It is very easy to understand! In Spain Cananbis seeds are completely legal!
As they have no THC. No matter if the seeds are birdseed hemp or powerful Thai. You can carry by the street a 50 Kg bag (of clean seeds with no vegetable material) and go to a police station talk with the policemen there, tell them jokes and later you go to your home with your 50 Kg Thai seeds! They would be alarmed if you carry a bomb or any weapon in the bag, but not for the seeds!
Of course as they hold the pan by the handle they can annoy you. So I don't recomend you go to a police station with a big bag of seeds
You will not go to jail for smoking or carrying a small amount of weed or hash in the street but you will get a wonderful fine from the Spanish Administration from 600€ onwards! Depending if the authority agent has spent the previous night in the sofa or any other unknown circunstances!
On the other side growing plants (there is no number or size) is a legal offense and you can go to court and even to jail! Prepare yourself to pay a lot of money to the fantastic and awesome Spanish Judicial System!
Not long ago they weighed the soil and even the clay pots so you were amazed in the news by plants producing 20Kg of the dangerous substance!!! If they find an indoor closset it will appear in the newspapers as a drug lab!
Most Spanish breeders are only scammer entrepreneurs. They take a few famous clones, buying them or even from some forums. Among those clones Critical Bilbo is essential, Amnesia Cordobesa, Widow Poligonera,... any fancy name which rarely must something to do with the real origin of the clone. Also any female from a pack of Jack Herer... They take cuttings. They spray them with Siver Thiosulphate, et voilà
! Around 10€ per seed or even more! Those seeds usually are sold more expensive than the original strain!
Some of those "breeders" give clones to other people or friends who make the seeds at home in their closets. Others hire a flat or chalet for that purpose.
Other times they buy bulk seeds and introduce them in a fancy package with an atractive name and overrated hype. I bet they spend more in their webpages, hype and marketing than in properly breeding and making the seeds.
That's all folks!