Basil & Catnip Fail to Germinate

Question

I'm trying to germinate some basil and some catnip seeds. The basil is the regular, plain basil, like you'd purchase at any box store. I bought one of each of these plants in the spring of 2013 and put them in the garden. They did excellent. The catnip, especially, had to be cut back several times. At the end of the season I collected seeds from them.

Due to unforeseen circumstance, I wasn't able to plant a garden in 2014. It's now the first week in February 2015 and I'm trying to get some stuff started early. I can't seem to get my basil or catnip seeds to germinate. I collected them out of dried flower heads on both plant. I didn't think they were wet, but I let them dry a week before storing them in an air tight container with a small piece of paper towel to absorb any moisture.

I do that with most of my plants and I get the others to germinate with no problem. I can't seem to get these two to start, however. I've been using a wicking soda bottle to start them as it leaves the dirt lightly moist and doesn't compact it. I've had excellent success with other plants this way.

I read that basil needs to be warm, so I used a variation of the damp paper towel in a zip lock bag method. I took a roughly 1" cubed plastic container, put a piece of damp tissue paper at the bottom, placed the seeds on top, and put them in a warm dark place. I left them for 3 days before checking on them. I did the same with the catnip. They've not even started to germinate, but have started growing mold on some of the seeds.

All of my basil seeds, so far, have gotten that gel on the exterior of the shell, so I believe they're viable. The first ones, I probably planted too deep, at a .25". The ones in the plastic container should have been good. Now I've soaked some over night. I planted 2 seeds by pushing them into the dirt and barely covering them. The other three I just put on the surface an pressed in.

My room is the warmest in the house, but I can't say the temp doesn't dip. I can put the bottle in the warm draw, as the heat vents under the cabinets and keeps the drawers really warm.

I'm currently up to having used 15 basil seeds without one germinating. I'd love some help. Thank you.

Edit (2/25/2015): I have done cold stratification on the catnip and basil seeds. I put 5 seeds of each in 3 ziplock bags and I've put one in the fridge and two in the freezer. I meant to pull one bag of each out after a week and then pull the freezer bag out after a month, but my calendar didn't alert me properly and I removed them on 2/23/2015 after putting them in on 2/5/2015. I've planted them in a wicking waterer, under a 100w equivalent bulb in a warm room. I'll report back on germination, if any, at a later date.

Answer 1

Will probably take somewhat longer than a week to stratify the seed. I grow lots of catnip and never collect or stratify seed - what falls to the ground itself happily stratifies itself and comes up the next year, and I can now identify a catnip plant when it's less than 1/2 an inch across - so I just move them where I want them and pull the ones that are in the way if I have enough where I want them.

Unless you have relocated away from that garden, there probably was catnip last year and will be catnip this year...

If you have relocated, the best bet would be walk out, dig a hole in the snow, and sow the catnip seed where you want it, then put the snow back. The seed will take care of itself.

Basil seeds have mucilage, which you may be mistaking for mold. Opinions vary, but my recollection is that basil seeds like light, not dark, for germination - or possibly don't care. Might have to try the "paper towel and plastic wrap" .vs. "Paper towel and plastic wrap and aluminum foil" germination test to get some actual data on that. Basil seed I buy, normally.

Looking for something more authoritative without waiting for "do my own science", I found references to this in the literature. What I can't find is a good link, (but @J. Musser did.) so I'll just quote the abstract - anyway, this one suggests alternating temperatures rather than steady temperatures, and light rather than darkness.

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Age Environmental Factors, Germination And Seedling Emergence Of Ocimum Basilicum L

Ismail A. M. A., "Age Environmental Factors, Germination And Seedling Emergence Of Ocimum Basilicum L", Qatar University Science Journal, 1990, Vol. 10, Pages 155-166.

Abstract

• Fresh and exhumed seeds of Ocimuni basilicum L. gave 100 % germination at 13/11-h alternating temperature of 20/10, 32/18, 38/24 and 40/32 °C but did not germinate at constant temperatures.
• Germination was prevented in the dark but occurred with a 13-h photoperiod.
• With increasing age, seed dry weight was reduced progressively as with speed and extent of germination; seeds 5 or more years old were not viable.
• There was 90% emergence from seeds sown on the soil surface but only 33% produced seedlings when buried 2 mm deep and emergence was 20% or less from those sown at depths of 5 mm or more.
• Mucilage by the seeds apparently helped to prevent desiccation. The ecophysiological significance of the result is discussed in relation to weed control in the Sudan Gezira.

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