1) Has anyone used a heat mat with the 2 liter soda bottle SIPs?  Would it work if they were inside a tupperware humidity chamber?

2) For those starting cuttings in coir, after wetting it, do you squeeze out excess water and pack it into cups, or do you just leave it in there more fluffy like?

3) Finally, if using an upside down tupperware as a humidity chamber on top of a heat mat, does it matter if the center area of the upside down lid (where the cups are sitting) is elevated and thus not in direct contact with the mat?  It seems like all tupperwares cup in on the lid, which becomes a little mound when upside down.  Similarly, I'm considering turning the tupperware into a giant sip mat with all of my cups sitting on it.  Would the heat mat still be effective?
I guess this question really comes down to whether the heat will radiate into the chamber and the chamber temp is what really matters, or whether contact with the heat mat is critical?

4) As a bonus question, if i use the same tupperware for a humidity bin that I used last year and I had a bad fungus gnat infestation in my cuttings last year, do I need to worry about there possibly being dormant eggs somehow in the tupperware that will hatch when it gets moist in there or can they not survive that long?

Numbered them for ease of answering.  Thanks in advance!

Timmy,

1. I use a heating mat for my cuttings, and for the most part they are directly on top of it. I think as far as heat transfer, you will not get alot directly from the mat, but will get enough.  I would also watch out for temperature, unless you have a thermometer.  I set mine at 77 degress.

2. As far as coco coir, I spoke to a friend who was using straight coir this year and he found that it tends to stay pretty wet, even when runged out.  He suggested that I use a mix of 50/50 coir/perlite. 

Hope this helps you with some of the questions.

I'm using a system similar to what you describe - I have a plastic storage bin right side up with the 2 liter SIPs sitting on the bottom.  The heat mat is underneath of (i.e. outside of) the storage bin.  The heating mat/storage bin is sitting on a small wooden table.  The amount of insulation on the other side of the heating mat seems to affect how much heat give off to the storage bin.  I use the lid to the storage bin as well but keep it ajar so that the temp stays around 74-80 degrees inside the bin.  I am wrapping my cuttings with parafilm so the only function of the bin is to be a space for controlling temperature at about 10 degrees higher than the ambient room temperature.  In my case humidity is not an issue since the exposed part of the cuttings are wrapped in parafilm.  In the SIPs I use a 2:2:1 ratio of coir/peat/perlite.  I'll try to post a photo later.  I started my cuttings about 8 days ago so not surprisingly there are no visible roots or leaves yet.

I guess you are using the storage bin upside down to trap the heat, correct?  Whatever works for you to keep the temperature where you want it should be fine.

I am trying coir this year for the first time.  Starting with a 2 part coir/ 1 part perlite mix.  One thing I did do was rinse out my coir.  I was using no name bricks from the local hydroponics store and was concerned about salts.  I bought an inexpensive "total dissolved salts" (TDS) meter on ebay.  I initially added about twice the required water to the dry coir, strained the material after about an hour and tested the excess water with the meter and measured almost 700ppm of salts.  I flushed the coir two more times and finally got the excess water down to about 140 ppm before I mixed it with the perlite.

Thanks for the input so far.  upside down for heat/humidity dome and ease of access for watering.  Haven't made my mind up on which ways up yet, hehe. 

Rewton, have you tried that method before?

twovkay, i planned on using at least 30-40% perlite.

Bill, i started soaking it last night.  wasn't going to strain bc i didn't know what i could use that would catch the fine particles without them going through the strainer.  Maybe i'll still do it tonight.  i'm using beatspeat coir.  i thought someone said on here that it was already rinsed.  is the tds the same as specific gravity meter used for salt water aquariums?  i also used calmag in the water when i mixed it.

Timmy, I've used the 2 L SIPs before with success, and I have used a storage bin and heating mat to control the temperature for cuttings, but this is the 1st time I have used the two together.  This is also the first time I have tried the parafilm method.  Re. gnats I taped a small square of nylon pantyhose material over the vent hole in the lower reservior of the SIP to block gnat access and then layered on about 1/2 of play sand over the top.  So far no gnats.

I just poured it through a food strainer I got at Ikea.  The strainer mesh size was similar to window screening and there was not a lot of fine particles in the excess water.  As far as the meter goes this is the one I bought on ebay.  It is supposed to measure the total amount of dissolved salts in the water in ppm (parts per million). 

http://www.ebay.com/itm/261712389553?_trksid=p2060778.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I am trialling straight coco in a few cuttings. These were the cuttings from Bill that he sold recently. The pics are of UK Pastilliere. These were put directly into coco and the tops were covered with bags. I also have others looking the same as these. So far so good. No mats just humidity and warmth from the house,68 degrees typically. This next week i will start opening bags to acclimate.