Jiffy Mix vs. Home-made

I typically start seeds in Jiffy Mix and then transplant to a regular soiless mix once the seedlings are large enough to handle. This year I decided to make my own mix.

1 Part Peat
1 Part Sterilized Compost
1 Part Partially Composted Bark Fines
1 Part Perlite

The seedlings seem to continue to grow, but they have all taken on a somewhat purple hue. I've included a photo with the younger seedlings on the left grown in Jiffy next to the older ones in my own mix (same variety). The ones still in the Jiffy mix are bright green. Is there a nutrient deficiency? or is the mix too rich? Maybe too acid? Any help would be appreciated.

Pictured: Laurentia Seedlings

This message was edited Apr 9, 2007 8:01 AM

Are you starting them inside, with heat and lights, or outside? Are you fertilizing yet? I wintersow seeds (outside, in winter, in covered, vented containers) and when cold the seedlings take on a purple hue then green up when the weather warms. With this cold snap, my babies are pretty purple right now, (it's 29 degrees and I have 60 containers of seeds out there) but they will be green soon. Summer does have to come eventually, right?

Wintersowing is becoming a popular, easy seed-starting method. No damp-off!. If you're interested check out the wintersowing forum here on Dave's.

Karen

They are indoors under lights. I used a heating mat until the seeds were up. I haven't fertilized hoping that the compost would provide necessary nutrients (I didn't fertilize the Jiffy Mix either). The area can get cool at night (as low as 55), but both seedlings are exposed to the same temperatures. I have used a week Hydrogen Peroxide solution when watering to control damping-off, but it seem that the color change is universally associated with the type of soil. Everthing in the Jiffy Mix is a bright green and everything in the Home-made mix has taken on a purple hue. The two types of soil are in the exact same environment and get the same treatment.

Well, I'm no expert. But the 1/4 compost in your mix might not be enough fertilizer. I generally start adding a weak, dilute fertilizer once the first true leaves appear. Since the Jiffy ones are bigger I suspect they are getting much more food (fertilizer) than those in your homemade recipe. And possibly showing the purple due to their size, but that's just a guess. After this cold snap many of my outdoor seedlings are looking kind of purple, but they did that last year and stayed extremely healthy and turned greener as soon as the temperature got warm.

Also, if you were getting any help from the beneficial organisms in the compost I'd think you kill those organisms, too, along with the fungus by watering with peroxide.

During this cold snap I did move some of the more tender seedlings, like zinnias, to my unheated garage (probably only temps in the 30s or 40 at night), at night, but left about 20 containers outside through everything. Some of those look purple but no frost damage even though our temps were in the 20s with winds chills in the teens for several days.

I'd try moving to a warmer location and see if that alone helps before doing anything too drastic, and I think I'd fertilize them too.

Karen

My bad. The smaller plants on the left are in the Jiffy Mix, the larger plants on the right (which are more purple) are the ones in my mixture. I'll try a week fertilizer. I just don't want to over do it.

Thanks Karen

Thanks for posting this, I'm really curious about this subject.
I think your mix is probably on the acid side with peat and bark making up half of it? I mixed my own soil for winter sowing in a similar ratio, (some of it anyway, after I ran out of bags) and I have quite a few reddish seedlings too. I don't think it's a problem, they look great to me. (yours and mine)
I added lime to some for plants that I know need it, and next time I'm going to try adding some kelp meal or similar micro-nutrient fert.
Don't add it because I'm saying this, but phosphorus deficiency can make leaves that color too. I don't know about seedlings though.

This message was edited Apr 9, 2007 8:09 PM

willmetge: You have D-mail.

Karen

Have you considered having a soil test on your mix? That should tell you if you are deficient in any nutrients.