Ever wonder you buy a packet of seeds from your local garden center and when you open it up there are like 500 seeds in there? Why do you need 500 tomato plants? Are you suppose to plant all of them? What do I do if all 500 sprout???
I have often wondered these very same things.
Holiday displays are starting earlier and earlier each year. This year I seen Christmas items in stores in September! One isle was Halloween the next Christmas! What in the world! Last February when my son broke the zipper on his coat - I had to go to about 8 stores that were all selling bathing suits before I found a few back in the corner on the clearance rack which he had to settle for and one that he didn't very much like at all :(
Well, the same thing happens with displaying seeds. They become available in stores way before the ideal planting time. Even if you were going to give them a head start and grow them indoors they are months too early to get started. And what happens is that they are not being stored in ideal conditions. Many times they are sitting on shelves in full sun, being exposed to humidity and open to the air which decreases germination. And for how long? Every year seems to be getting longer and longer. And that is not to mention shipping temperatures. Were they exposed to extreme temperature fluctuations in the back of the freight truck?
The bottom line is that there are many environmental factors that decrease the germination rate and to compensate for this seed companies provide "extra seeds".
The problem with this method is - how do we know which ones will sprout?
Well we don't.
So the package tells us to plant let's say several seeds per hole. Then go back and "thin" the plants down to one, if more than one seed germinates. The problem with this, besides that it is just one more thing to do - is that in general gardeners don't like to needlessly kill things and that is what "thinning" is. So in some holes there is nothing growing and in other holes there are plants growing and now you have to kill 13 of them per how many holes :(
1 Purchase seeds that are properly stored
2 Buy from a company that prints germination rates on the package
To properly store seeds they should be minimally exposed to:
Online is a great source to purchase seeds as they are stored in the above means until your purchase.
What is a germination rate?
The percentage of seeds that actually germinate, based on growing out 100 seeds
100 seeds are use as the base number, you do not have to start 100. ie If you start with 10 seeds and only 8 sprouts or germinates then your germination rate is 80%
Germination rates that are provided on a package are a great way to figure out how many seeds to plant without having empty holes and killing an overabundance of tiny seedlings. For example if the germination rate reads:
95% or above I usually plant 1-2 seeds
85-95% plant about 2-3
75-85% plant 3-5
below 75% plant 5+