lavender germination experiment

[tantric]

I'm trying to get some information about the factors that influence lavender seed germination. this is actually my second experiment, the first ended when I transplanted the seedling and they all up and died.

I used to be a scientist, I know this is a monster of bad experimental design, but I need data, now....

the factors are: true lavender vs munstead, peat pot vs homemade can pot, 24hr freeze vs no freeze.

I've learned that lavender seeds like high humidity and barely moist soil to sprout, so this is a universal condition in the experiment. I'm using a 20gal aquarium with a 65w CF bulb on a timer....12/12 I guess. I took a long piece of plastic wrap and taped it to the bottom of the tank, then put the cans/pots on it - it's long enough so that I can lay it over the pots to keep the humidity high. the soil is a 50/50 mix of sand and potting soil, which worked well last time. the cans have rocks in the bottom for drainage.

we have thirteen subjects (JP=jiffypot, Mun=Munstead, TL=True Lavender, NF=no freeze, F=freeze):

• 1- jP mix NF
  2- JP Mun NF
  3 - JP TL NF
  4 - can TL NF
  5 - can TL NF
  6 - can Mun NF
  7 - can Mun NF
  8 - can TL F
  9 - can Mun F
  10 - can mix F
  11 - JP Mun F
  12 - JP TL F
  13 - mystery can, no idea where it came from

[applestar]

I don't think 24 hour freeze is going to do anything. If you want to cold stratefy, isn't it more like a couple to a few weeks?

I might have posted in more detail at some point, but I just grabbed an entry from my seed starting log earlier this year for Lavender Munstead :

Herb/Flower, Lavender, munstead Jan 28, 2015 Paper packet atop pudding cup of UltraSorb covered V8-2 --> WP1 Feb 24, 2015 27d WP1 "Feb 18, 2015
Feb 24, 2015" 1/27-28 soaked in a paper packet of rmtmp/WP2 water; 1/28 start stratefying in V8-2 for 3 wks >> Feb 18, 2015 sown in pumice, UltraSorb, potting mix,monad and dolomitic lime mix in 3" terracotta. Covered with bev lid. @WP1 >> 2/26 discovered they had sprouted >> removed lid

* WP2 is my Winter Paradise indoor greenhouse on 2nd (upper shelf) level... in late January -- so we are talking about mid/high-70's °F daytime and mid-60's nighttime.
* V8-2 is my unheated garage V8 nursery on 2nd (upper shelf) level... Jan 28 for 3 wks would have been low 30's to 40's but not freezing under the lights during the day, could have gotten as low as upper 20's during the night with the lights off (unless we had an exceptionally cold snap then it could get as low as mid-20's in the garage but not likely on the V8 shelves -- I would have protected against that). The UltraSorb would have been moistened.
* WP1 was probably low/mid-70's day, low 60's at night by mid-Feb.

[rainbowgardener]

Lavender seed does not need light to germinate, so you don't need the bulb until you have some sprouted. After that your light should be on 16, off 8. And I'm thinking with them in an aquarium, doesn't that mean the light is at the top of the aquarium and the just sprouted seeds are at the bottom of the aquarium? Once you have tiny sprouted seedlings, the light source needs to be just a couple inches above them. (Light intensity varies by the square of the distance, so seedlings with a light 4" away are getting one-quarter the light as seedlings with the light 2" away.) The soil needs to stay warm, like probably 75 (deg F). Best is bottom warmth, because what needs to be warm is the soil, not the air. I start mine on heat mats. Personally I don't worry about the humidity. The seeds are in the soil, so they are going to stay damp, because you are going to keep the soil damp(ish). Once the seeds are sprouted, the humidity is very bad for the seedlings, makes them vulnerable to damping off and other fungal diseases.

None of which is relevant to the variables in your quasi-experimental design. One that is, is the peat pots. I hate them. I do all bottom watering and in that condition the peat pots tend to get moldy. But even without that, they hold too much moisture, so the soil stays too wet. If you finally water little enough to prevent that, the peat starts drying and sucks water away from your seedlings.

I was going to say you should plan on keeping them indoors all winter, but then I realized you are in Athens, GA and you don't HAVE winter. But anyway, be aware that this is a slow project. In best conditions, they usually take a couple weeks to sprout, can be up to a month. After that they grow very s....l.....o....w.....l...y. I usually start lavender seed in late Jan or early Feb. By Sept or Oct when it is cold enough here to put them into dormancy, they are maybe four inches tall or so. The second year they do much better.

Best Wishes. I love lavender! Even though it takes a bit of patience to get started, it is so worth it!

PS. I just looked back and saw where you put rocks in the bottom, "for drainage." People always used to put gravel in the bottom of containers "for drainage," but that was always a myth. It turns out if there is a sharp border in textures, like between potting soil and gravel, water will not cross the boundary, so you end up with a flower pot with dry gravel in the bottom with soggy potting soil sitting on top of it. The water tends not to pass the barrier between soil and rock until the soil is saturated, which is not what you want.

https://puyallup.wsu.edu/~linda%20chalke ... ainage.pdf

I don't know how far along you are in your project, but if the seeds are not planted yet, I'd go back and take the rocks out.

PPS re the freeze- no freeze condition. I agree with Applestar, that 24 hr freeze seems not too likely to accomplish much. And you do know that just freezing the seeds, does NOT count as cold stratifying? That's just storing them. To cold stratify, you have to plant the seeds in moist potting mix, wrap the whole thing in plastic wrap to hold moisture in, and then freeze/ refrigerate that. The stratification process involves chemical reactions in the seed which break down germination inhibitors. These reactions only occur at cool/cold temperatures in the presence of moisture. These are usually slow processes, which is why 24 hrs of cold stratifying may not do much.

[imafan26]

I started Lavender in a mini greenhouse, aka grape container from Costco. Media perlite.

Lavender requires good drainage and does not like a lot of fertilizer. Rainbow is right, lavender does not require light to germinate. I put a paper towel over the media and water over it to keep the seeds moist but not soggy. The paper towel also helps to keep the seeds from moving so they have a chance to establish. The paper towel was removed once most of the seedling were sprouted.

Germination took approximately 3 months and seedlings grew very slowly. Misted to keep media moist but not soggy. Small plants cannot handle heavy watering overhead. I don't bottom water, but that might be something to try as long as it is only soaked until the media is wet and then removed.

Seedlings got to be about an inch tall before the snails got in the container and ate them all.

I do lavender from cuttings now.

[rainbowgardener]

I don't know if you are still around tantric, or will come back.

If so, I was thinking more about that aquarium. It is ok for the seeds, but will be very bad news for the seedlings once sprouted. No air circulation.

Damping off is a fungal disease that young seedling are prone to, that nearly always kills them if they get it. It is fostered in conditions of high humidity and low air circulation. Your aquarium is both. At least once the seeds sprout, you are going to need to get them out of there.

[Susan W]

Oh the lavenders! I have seed starting going 12 months, especially as I do a variety of perennials, and a few hundred starts in varying stages at any given time. I don't use heat mats or special lighting, start in peat pellets (10 or 12 to tray), top water, kitchen window with a couple of regular lights. Warm months are so much easier! I start inside where I can watch more closely, then set them out in light shade sheltered space.

I started messing with lavender maybe 2 yrs ago, and had a few plants out for market last summer, testing one plant in a pot on my deck (it's doing fine). I plant seeds as mentioned. Have munstead and vera going now, vera not doing anything. Other about 50%. I do over seed trying to get at least one to show in a peat pellet! Note, if you have a batch not doing anything, try from a different source. It doesn't mean the one company is bad, just different batches, age of seed etc.

Once the seedling is up showing true leaves, up it to a 4" pot. For convenience as much as anything (and it works), using Miracle Grow potting mix. These pots get moved into more sun, never full blast in the summer. Once big and doing, I bump up to qt size pot. This could be 6 months to year from start.

I'm thinking of inventory for next season, and that is a big part of my trial and error micro business peddling at the farmers market.

A question for you, tantric. Are you hoping to grow lavender on your place or sell starts?

[Susan W]

This discussion got me to thinking about more lavender. Today seeded 4 trays, 10 pellets each, with Munstead, 4 different sources. Then did a 1/2 each of Vera and one named True (could be vera). They are by a window, no direct sun, temps low 80's (I keep the house warmish!). If even third to half do will have plenty! I have to think ahead to January about size of pot per plant, how many etc. Space is easy in the warmer months!

[tantric]

this is my previous experiment, which ended when I tried to transplant them and they all just vanished:

part one:
although it's not really scientific, for lack of numbers and the right control groups, I decided to do a little experiment on lavender seen germination. I started with two varieties, Burpee True Lavender and Munstead, though I think I got some of the seeds mixed up, so I wouldn't take that part as being important. my test conditions are: soaking in a paper towel for two hours/not soaking, freezing overnight in a damp papertowel in a ziplock bag/not freezing and planting on a damp paper towel/surface of the soil. all of the seeds end up in a shallow dish with 50% potting soil/50% sand under a 20w lamp, misted often then covered with plastic wrap. I started on June 11, 2015 with these groups:

1)10 seeds, wet for 2hrs, frozen and sown on soil
2)10 seeds placed on a damp paper towel and immediately frozen then sown on soil
3a)10 seeds, true lavender, sown on soil
3b)10 seeds, munstead, sown on soil
4)20 seeds placed on a wet paper towel for 2hrs, then the PT placed atop soil in bowl
5)20 seeds wet for 2hrs, frozen for a day then the PT placed atop the soil

part two:
today, on the 15th, I have 3 sprouts from group 4 and 2 from the mundstead that were place directly on/in the soil. I'll update in two days - science, y'all, cause it works.

part three:
I transplanted the sprouts today. for those in soil, I used a pair of reverse forceps (squeeze to open) with the tips bent so they don't quiet meet. dug around them a bit with a mini flathead screwdriver first. I had jiffypots prepared, 1/2sand+1/2PS, made a hole as you mentioned and lowered the seedling into it. the ones on the paper had grown through it, so I just cut around them and planted them with little paper dresses. the count now stands at:

4)20 seeds placed on a wet paper towel for 2hrs, then the PT placed atop soil in bowl - 4 sprouts (embedded in PT)
3b)10 seeds, munstead, sown on soil - 4 sprouts
1)10 seeds, wet for 2hrs, frozen and sown on soil - 3 sprouts, all I believe to be munstead

for lavender, that's outright prolific. but there's not really a clear trend in the data. I'll try a new set of conditions with the next set.

btw, if I grow these for a month or two then put them out, will they survive the winter?

---------------------------------

the only thing I can conclude from the first experiment is that it does not in any way take 20 days for germination and that the seedlings don't like to be transplanted.

I'm an aquarist, so the light over the 20gal tank isn't a paltry 15watt bulb - its a 65watt compact flourescent, so does that still need to be closer? I know the light-loss law by heart

my current problem is that just after I started this experiment, I got knocked out by a summer cold and ignored it for 3 days. not sure if I want to start over or go through with it, but I can assure you the seedling will get circulation - I have a fan for that. heck, there's a fan in the light fixture. with this batch, I sowed them in their pots and froze the pots, if that helps.

[tantric]

UPDATE: (alert the press!) in my new experiment, I have a seedling, from a can, frozen munstead group. it's about 2". I'm thinking lavender likes to dry out in the soil and have humidity above, but we'll see. this does mean I'm not stopping the experiment.

[rainbowgardener]

Thanks so much for coming back and keeping us posted on the outcomes!

Congratulations on having a bunch of little lavender seedlings started.

Re: I'm an aquarist, so the light over the 20gal tank isn't a paltry 15watt bulb - its a 65watt compact flourescent, so does that still need to be closer? I know the light-loss law by heart . Yes your 65 watt light still needs to be closer. I use t-5 fluorescent tubes with lots of lumens per watt and I still keep them a couple inches above the seedlings and on 16 hrs a day. The 16 hrs is to try to make up for the fact that it is so much less light than even a cloudy day outdoors. Our eyes are so efficient at adapting to different light levels, we don't even realize. Stand outside your house on sunny day sometime and look in the window, see how dark it looks!

And I still think your plants are going to need to get out of the aquarium very soon anyway so the humidity and lack of air circulation doesn't kill them. Damping off is heart breaking when it occurs!

[applestar]

I've been meaning to post this photo here.
These are my Lavender Munstead HIdcote (I think) -- that really need to be planted in the ground

The middle one that is blooming (it's growing sideways because the pot got knocked over ) was actually started for last year but wasn't planted in the ground, so I overwintered it in the garage V8 Nursery.

The ones in the large and small pots were started this winter.

It's not too much trouble to cold stratefy by putting the container with seeds sown in dampened medium in the freezing garage for a period of time, and after 2nd year, I'm feeling more comfortable about it, but it would sure help to know how to go about starting them at other times of the year.

I found that the lavender seedlings responded well when sown in sandy mix in plastic container with plenty of drain holes -- I've been using berry container, placed on a drip tray filled with 1/2" sand. Keep the sand moist. Then uppot to clay pots like these.

[tantric]

the results are basically that nothing makes a difference but the seed - Munstead works, the other doesn't sprout. as for damping off, I have mushrooms growing in two pots, I'm going to save them and sprinkle the spores whenever I do high humidity work, on the theory that they are competitive with the dampening off mold. pics and details later.

[tantric]

results:
one can with Munstead, frozen 23 sprouts
one can with true lavender, frozen 4 sprouts
one peatpot with Munstead, not frozen 4 sprouts
one peatpot with mixed seeds, not frozen 11 sprouts

which is really frustrating - no conclusion. I know that lavender seeds like to sprout atop 1/2sand 1/2soil that is damp but never watered in humid conditions (covered with plastic wrap and misted) - they will sprout within 5 days or never. I had mushrooms sprout in two pots, but no dampening off. from the next experiment, I'll heat sterilize the soil first. I also saved the mushroom spores, as I'd assume they would be competitive with mold - the didn't seem to harm the sprouts at all.

[tantric]

these are the pics

[rainbowgardener]

Nice -- teeny, baby lavender seedlings. Be prepared to nurture them along for a couple months before they look anything like plants.

I still hate the peat pots. If your little seedlings start looking at all shrivelly or browned at the leaf edges, that is a sign that the soil is staying too wet.

[tantric]

the seedlings do prefer the cans over the peat pots.

I started a new experiment with true lavender only. still using peatpots and cans - I'm recycling the old ones, I just heat sterilized them. I mixed up the TL seeds and some soil and evenly distributed it through the pots. control group goes under the 12/12 light and mist, the rest are in the freezer. I stirred the seeds in the soil and moistened it before putting it in the freezer, then covered the pots. one group will freeze for 24hrs, the other for 3 days.

at this point I have 2 tiny seedlings that might be true lavender, more likely munstead escapees. I'd *really* like to germinate some true lavender.

question: why do I often hear it takes 2-4 weeks for lavender to germinate?

originally, I'd planned to put these seedlings out in fall and let them over winter....but that was several unproductive experiments ago, so I'm thinking they'll stay inside this year?


question - why do I often hear that it takes 2-4 weeks for lavender to sprout?

[Susan W]

Lavender germination times seems to vary by variety, and the seed packet. In my last round, the munstead from an unopened packet sprouted the best. A few 'vera' are up, as well as a couple 'true'. Once up go out to a sheltered light shade area. When I tried the chilling (planted in peat pellets, put in frig) didn't seem to make any difference with lavender.

The babies are kept moist, and I try to water with Johns Recipe every week or so. Now I have coneflower (3 varieties), basil, lavender and more in the peat pellet baby stage. There's more behind these either just planted or in frig for chilling.
Once up with true leaves and when I get to it, the plantlet goes into a 4" pot, and I use Miracle Grow potting mix. This round should be up and nice, and probably stay in the 4" until next spring. Last winter I kept the lavender and other hardy starts outside. I used the mini greenhouse with plastic cover, is sheltered under eaves and against the house. Cover opened every day. They did fine and held their own. I got nervous and brought them in when going below 20.

As days got longer, temps warmer, not out of frost, bumped plants up to quart pots. This included the other hardy perennials such as rosemary, coneflower, rue, wormwood and more.

[tantric]

11 days later status:

true lavender, sown atop sand/soil mix, wet put under light - two of the cans have good sprouts, 3 and 2, but they look a lot better than the munstead sprouts did at first

true lavender, sown atop sand/soil mix, stirred a bit, well misted, covered then frozen for 24hrs - two cans have sprouts, 1 and 4, also healthy.

as yet none of the 3 day freeze subject have sprouted.

[tantric]

I've been growing my lavender sprouts for a minute now, and they're still less than a few inches high, 6+ sets of leaves. is this normal?

[rainbowgardener]

yes, normal.

From my post, pg 1 of this thread: After that they grow very s....l.....o....w.....l...y. I usually start lavender seed in late Jan or early Feb. By Sept or Oct when it is cold enough here to put them into dormancy, they are maybe four inches tall or so. The second year they do much better.


See also on pg 1 applestar's pictures of her lavender seedlings. Seed was planted "in winter." In her June post, they looked like a couple inches tall or so.

[tantric]

I'm guessing they really should stay inside this winter...

[Susan W]

Just continuing with the lavender....FWIW, what I do, and works sorta.

Today was working some small pots (3.5 -4") of this and that. Some had been shuffled, somewhat ignored. Anyway, had a few lavender -munstead, started last Jan-Feb, and upped them to qts. Had I tended them earlier, probably could have upped them earlier and had market ready. Well, hopefully they will be ready for next April! There are some small babies behind them. Not putting any more out for market this season, as I think they need to be re-homed, large pot or ground by 1st August to get a root system to sustain.

Where do they stay? Part sun. They will go to mini greenhouse sheltered on deck in Oct-Nov. I usually get frost 1st week Nov-April 15. Lavender isn't happy inside, and may just come in when below 20 or so. They are sheltered and have the plastic cover of mini greenhouse.

I am no expert, but willing to share what I know, mainly from trial and error- lots of both!

[rainbowgardener]

I'm guessing they really should stay inside this winter...

Have they been inside so far? If so, then yes, they should probably stay and you can harden them off in early spring and bring them out. But if they are outside now, then I would NOT bring them in. You are in zone 8. Most lavender is hardy there. The munstead/ English lavender I grow is hardy here in zone 6 (but not all lavender would be). So put them in a bigger pot or in the ground, mulch, and let them stay out and toughen up for the winter.

[Susan W]

Let's go back to the project. About how many starts do you have? What is your goal? That being to plant at your place or sell starts?

I wouldn't put any of the babies in the ground now. One they are too small to get any root system before colder weather. More important perhaps, it rains and doesn't dry out much Dec-March. Roots rot. If they are to be at your place, I suggest to work a raised bed for them with good drainage, and plant in spring.

FWIW, I'n not putting any more lavender or rosemary starts out at market until spring. It is getting too late for either to get a good root system before cooler and shorter days.

Your enthusiasm has me trying to get more lavender going! I'm even looking over the yard for a small place I could have a dedicated raised bed of it (most now is in containers). Is that good or bad influence??!!!!