Germination And Seed Testing
Seeds don’t all germinate, and sometimes they don’t germinate at all. Let us explain: on every seed packet (from reputable seed houses like Johnny’s) you usually see a statistic, expressed as a percentage, of their germination rate. It looks like this: germination = 94%.
What that means is that Johnny’s has taken several batches of these seeds and “test-germinated” them to see how good they are. 94% means that 94 out of 100 seeds they tried did germinate. When you plant them, that is what you should get.
However, something may have happened to the seeds on their way to you; they may have sat on a freezing or frying loading dock somewhere for too long in their little Post Office or UPS envelopes; this really interferes with the seed’s germination rate, or kills them outright. This can happen at home if you leave the seeds outdoors overnight (too cold!), or if you leave them on a sunny windowsill or in the sun anywhere (too hot!). So, keep seeds dry and warm indoors until you need to use them, then get them back to a protected spot as soon as you’re done.
The germination area and/or sprouting table MUST be around 75 degrees F; this will give you optimum germination and growth of these small plants when they are most delicate. Heat your germination area and/or sprouting table to this temperature if you need to, because otherwise, getting no germination is a possible outcome here. “Germination” is the period during which the little plant sticks its first roots out and puts out its first two tiny leaves. After 3 to 4 days, your seeds will have germinated into sprouts, and you can move them to your sprouting tables (which are fiberglassed, waterproofed tables like long trays; that’s in a separate post).
Getting Enough Light To Your Sprouts
Sometimes you will have difficulty getting proper growth in the period right after germination; you will notice that your sprouts are getting long and “leggy”. If you see this happening, you have a serious problem that you need to fix before doing anything else. This is called “attenuation”, and is happening because your sprouts are not getting enough sun. This is totally normal for little plants to do; they’re simply trying to get taller and hoping to get some more light when they finally get “up there”. There can be several reasons for them not getting enough light:
One: The most common reason is that it is wintertime (which is a low light period anyway) and you are in the middle of an extended cloudy period which reduces the light that reaches your plants even further. There just isn’t much light coming in to the baby plants, and they‘re attenuating as a result. The fix? Get some artificial light on them as soon as possible, in the appropriate amount. There’s a document covering artificial lighting in your DropBox files called “Lighting For Aquaponics.PDF”.
However, even if you get lights on them right away, they may already be gone. If they’re already attenuated, it’s too late. Here;s why: if a batch of sprouts gets attenuated, they are already “shocked” to an unknown extent, and you have a bunch of plants that may have poor growth all the way through to harvest time. Adding lights after they become attenuated may not fix it; the plants may be past the point where the additional light will correct the situation. And by poor growth, I mean they may only weigh one-quarter (or less) what healthy plants that got enough light when they were germinating would weigh, but you will expend just as much labor harvesting them as you would plants of full weight. If they were badly shocked, they may not even grow that well.
Get the lighting installed before you germinate the next batch of sprouts or you’re likely to have the same problem on an ongoing basis. If the sun comes out, you don’t have to pay for electricity, but if you don’t have the lights, you may lose much of your production.
Two: A second common reason is you have put a second layer of plastic film between the sprouts and the sunlight. This is easy to do if you see your sprouts getting cold; you may figure you can cover the sprouting table (which is already inside one layer of plastic inside the greenhouse) with a layer of plastic to help ‘keep the heat in”. What you weren’t aware of is that each layer of plastic will block from 14% to 25% of the available light; with two layers, you are losing 28% to 50% of the light! Half the light gone! Don’t put two layers of greenhouse plastic over the sprouts to “keep them warm”, for this will keep the sunlight off also, and they will grow poorly. How to fix this?
Your germination area and/or sprouting table MUST be around 75 degrees F; this will give you optimum germination and growth of these small plants when they are most delicate. Heat your germination area and/or sprouting table to this temperature if you need to, because otherwise, getting no germination is a possible outcome here. “Germination” is the period during which the little plant sticks its first roots out and puts out its first two tiny leaves. After 3 to 4 days, your seeds will have germinated into sprouts, and you can move them to your sprouting tables (which are fiberglassed, waterproofed tables like long trays; photo soon).
Here’s a link to plans for a “Seed Germinator” that one of our students has used with success: it’s made from an old refrigerator, so has limited space for a larger commercial operation, but it will give you an idea. $18 from Amazon.com at the following link: How To Build A Seed Germinator With A Junk Refrigerator.
How To Correct Poor Germination If You Don’t Have Time For New Seeds
If you find you are having trouble with germination on a particular species, and there’s not enough time to get new seeds ordered and shipped, then plant two or three per pot, and thin them by hand at this point back to a single plant, before they go into the rafts. If you are only getting 50% germination with the only seeds you have, planting two to a pot will almost always ensure that one comes up! It’s more work, but contrast this to having only half as many plants come up and having to cull half your pots at transfer time!
IMPORTANT! Every time we get a new batch of seeds we sprout 100 to see what the germination rate is. This way, we know ahead of time if a batch of 50,000 or so seeds is bad, and we’ve checked them ahead of the time we actually need to use them, so we don’t get caught with our pants down and not enough time to order new seeds.