I intially started my fall seedlings in coconut coir seed cells. The second batch were started in peat cells about a week later.
There is a huge difference between the seedlings. The ones in the peat cells are very healthy and large, about 3 times the size of the ones in the coir. Moreover, the ones in the coir are very stressed. Their leaves are yellowing and the stacks are purple.
Nothing is different between the seedlings except for the type of cells. Same light, starting medium and even the same types of plants.
Has anyone else had similiar experiences with coir?
One issue could be that they need fertilizer--coir doesn't have any nutrients in it unless you add them. The seedling will sustain itself for a bit with the seedling leaves, but once they have their true leaves if you don't give them some fertilizer (diluted so as not to burn), they would tend to look a bit sickly. The other possibility is that coir can tend to be high in salt--most reputable sources selling it for horticultural purposes ought to supply coir that's been washed/salt removed, but if you've fertilized and they're still not looking great then that's another possibility.
Also worth noting that coir IS considered environmentally friendly. The whole reason you find coir based products out there today is because of attempts to find more sustainable/environmentally friendly substitutes for peat. Not saying coir is perfect--I don't know enough about all the processes involved in making it, but it's certainly more environmentally friendly than peat is.
Coir is not environmentally friendly when shipped over to here by diesel burning, smoke spewing ships.
The peat bogs in some parts of the world may be becoming depleted, but not here in Alberta.
I prefer to support local business.
My spring seedlings did better in coir than in peat pots. I did find that fertilization was the key to keeping any of them looking decent, though, so I kept up a regular routine. That said, I probably won't use either peat or coir pots again--they seem to keep my seedlings either too dry or too wet. I'll probably reuse all the small nursery pots I collect over the planting season.
Both coir and peat moss have little in the way of fertilizer in it. The seeds themselves have enough nutrition to start growing, but not much more, using a seedling mix with fertilizer is a good strategy Don't blame the coir or the peat. I start seedlings on a seedling mix, and grow mature plants in coir. All grow well.
I'd consider the salt theory then--if the coir that your cells were made of was high in salt, that could leach into the potting medium inside the cells and high salt content would definitely not make seedlings happy. The only other thing I can think of is if coir and peat wick water out of the soil differently, maybe the seedlings in the coir cells ended up consistently a little wetter or dryer than the others.
I've seen a few sources report that coir from many commerical sources has a lot of salt in it. One site advised at least three flushes, "pressing" excess water out each time.
For me, a little coir fiber mixed into heavy clay soil seems to aerate it better than peat moss. And I have lots of rain three seasons out of four, so any salt that came with the coir long ago washed away downriver to the sea.
I've stopped using it in potting soil because I'm too lazy (or busy) to rinse rinse rinse my soil components. Maybe if I were smart I'd leave a few bales in the runoff through one fall, winter and spring. Hmm, why not?
I decided to sow my seeds in coir this year because I had a problem with gnats last year. They came in via some invested seed starting mix. I know that most peat mixes are not pre-infested but had read that the gnats don't bother as much with coir.
The coir-sown seeds germinated fine but were in trouble as soon as true leaves appeared. The first true leaves were pale and many of the seedlings died. Here are some pics. These are all petunias.
First, a closeup of green cotedylons (I know that's misspelled) but pale true leaves.
And the final picture is of healthy peat-started petunia seedlings transplanted up into Promix.
Note, RickCorey, that the one on the right is yours from the Robin.
So could it be too much salt? The seed starting peat mix had no fertilizer either. It is Fafard. My (grown) daughter Kat, who gardens with me, tried to help the pale seedlings by bottom watering in diluted MG. Would that have added more salt, and compounded the problem? (I just came across this thread today and didn't know about too much salt in coir.)
If the seedling(s) raised in the coir and transferred to the peat don't make it, you probably were saved a lot of trouble, because IME, seedlings that start out weak usually grow into weak, disease- and bug-prone plants.
I have been hearing a lot of stuff about coir stunting seedlings. Some people say coir is full of salt, others that it's heavy metals. Whatever, it seems to be a problem for a lot of people, which is why I am sticking to peat for now.
I delighted to see my "mongrel" petunias going strong! I was only able to find a few pods last fall, and only one of those pods had any mature seeds. (Late start, early rain, low polination rates?)
I'm going to see how those 10-15 seeds do this year (I think they are now F4 hybrids from several commercial varieties back in 2009 - especially "Pearl's Royal Blue" from Burpee (I think). But mostly I;'m planting petunias I got from swaps. This time I'll try to keep varieties separate.
I heard the suggestion that we "flush" coir before using it. Hydrate it as usual, but then let water run out and try to wring it like a sponge, or squish it to expell as much water as possible. Soak again, squish again.
Or live in the Pacific NorthWet and just leavee it out in the rian for a few days! I like the coarse fibrous teture and would like to use more of it.
This year, I used Burpee's Eco Friendly Seed Starting Mix which was made from the coco coir. It also had some composted natural fertilizer added. The seedlings did ok then quit growing and turned yellow. I am very disappointed with the results from this medium. I won't use it again. I wasted time and money on seeds that sprouted, turned yellow and died. I even tried adding a very weak solution of plant food, a pinch or two to a gallon of water. Only made things worse. Very frustrating. Those seeds I planted in peat based medium are normal. Too late now to replant the seeds. Never again.
I tried making seed-starting mix mostly from screened pine bark muclh, to get more air into the mix and have faster drainage. Despite over-watering, it worked very well for every seed type except petunias. They need light to germinate, hence "sow on surface". My mix was so coarse that they fell into the cracks and were nev er seen again.
Next time I would sow very fine seeds onto a layer of vermiculite laying on top of the pine bark shreds.
Also, for big seeds, I would screen the bark shreds coarser ... rather, I would work harder to get rid of as many fines as I can.
yeah i started these roma tomato in perlite. then transplanted to either peat, perlite, fresh pine bark fines, or composted pine bark fines. all are fed with chemgro 10-8-22. my experience with bark has been poor. this pic is a week old. there is even greater differences now. the peat and the perlite plants are twice the size of the ones in composted bark. the one in the fresh bark is ok, but not as good as the peat or perlite.
from left to right. peat ,perlite (i covered the top with bark to stop evap), fresh pine, and composted fines.
I am using coconut coir for more than 2+ years to keep garden in healthy condition which saves water. Coir is a very popular planting medium for environment friendly gardening. It is the best alternative to peat moss with long lasting effects.
Till I don't notice any bad effects of using coco coir in gardening. I think you have to consult it with the local coco coir manufacturer or supplier i.e., They provide you the exact solution for your query.
Cocopeat which we buy should have a quality. It must be 100% composted, brimming with beneficial microbes and fertiliser, hydrated. Also it should be originated from the pure husk of the coconut without any addition of chemicals. High quality Cocopeat has unique aeration and high water-holding qualities. The pure Cocopeat is mixed with worm juice and nutrients and then composted to produce the best growing media. So, if we prefer pure Cocopeat, then yellow seedlings will not happen.