Regardless of the potting mix ingredients or the planter type (nursery pots or SIPs). Its as simple as finding out the actual amount of water that is needed to get your preferred mix "watered".

Since 99% of my cutting losses in the past has been to too much water in the potting mix or over watering, I had decided to test the effectiveness of mini-SIPs. While testing mini-SIPs (sub-irrigated planters) with fabric wicks for growing out rooted cuttings, I quickly realized that the SIP could easily water log the potting mixes if the reservoir or the wicks were over sized or if the reservoir was continually filled with water.  Checking the weight has been one of the usual recommendations for watering potted cuttings and fig trees, so I decided to quantify it. The dry potting mix in the container can be weighed and then watered, the difference is the maximum amount of water to be added when the mix is "dry". Since I do not have a kitchen scale, I was able to get the actual amount of water by adding water from a measuring cup to the dry mix until it was "watered". For my test SIPs, 2 liter soda bottles with 5 cups of seed starting potting mix (85% to 95% Peat based) it was 8 oz of water.

I also  realized that this test can be done on almost any potting mix to get the maximum amount of water to use for any small planter. The only commercial type mix that I have not tried are ones with moisture control Gels or pellets. The moisture control additives will increase the water holding ability of the soil mixes and should not be used in SIPs.

Once you figure out the correct amount of water for your mix and planter size, that amount is the maximum "Fill Amount" of water that is added when the mix needs to be watered. You are almost guaranteed to never over water again, and it will work for any planter type...

Edit... 12/2014

After testing, observing and measuring all the posted propagation techniques I've come to the realization that there are only a few variables that when controlled will result in very high success rates and it can be achieved with any rooting method, in any medium including only air.
...
1. Temperature, 72*F - 78*F and Humidity, 85% - 90% RH
2. pH, 5.0 - 6.5
3. Aeration, Well Aerated
4. Early Fetilization - in rooting medium or added once rooted.
...
1. When the temperature is maintained and the medium is kept barely moist, the humidity will usually remain in the optimal range.
2. The pH can be easily adjusted, and the pH of the used water should be, at least for the initial rooting and cutting stages.
3. The medium should be well aerated with larger particles, sifting will usually remove small particles and increase aeration.
4. Fertilization is dependent on the media used to root and grow out the cuttings. If an inert medium (Perlite, Scoria, sand, etc) is used, early addition of a dilute balanced fertilizer will ensure healthy continuous growth. When potting mix or soil is used the initial fertilizer charge will be able to provide initial fertilization, but early dilute fertilization is still required.

One of simplest rooting methods to date... http://figs4fun.com/Rooting_Bag_New_Style.html , the alternate cup method, the prior methods, procedures and explanations... http://figs4fun.com/basics_Rooting.html . The inner cup is clear and the outer cup should be opaque. Once rooted, the "plug" can be easily transplanted to 1 gallon nursery pots without disturbing the roots. The rooting medium should be any well aerated potting mix or inert materials. I currently use fabricated 2 liter sips that allow for a longer time period before its necessary to up pot to 1 gallon containers. The one addition to this method is a simple pre-soaking for 1 to 3 days, to hydrate the cutting before planting in the cup, it will decrease rooting time for stored cuttings.

Great info Pete, thank you for your wonderful insights.

Pete, you're right about water logging the potting mixes.  I recently separated my SIP's after noticing the uptake of water by the plants was not as expected (Since the buckets are white, you can see the waterline right through the side of the bucket.)  They had a little bit of a "swampy" smell and found this floating on the water in the bottom of one.

The water is obviously sitting in the bucket too long.  My suspicion is that the wick might be too large.  My other suspicion is that the roots have not found the water yet.  It might be a little of both.  Just to test the 'roots to the water' suspicion I took the cover off and watered from the top.  The plants responded right away!  So I will have to say the latter is more correct.  I'll have to wait for the roots to grow a little more and get on a steady watering schedule before I can really say that the wick is too big.  For now I'm letting them dry out a little.

Getting and maintaining the proper moisture level in the soil is very important so thanks for posting this Pete.  I do have a couple questions though.  When you start with a mix, it is not completely devoid of water unless you bake it, correct?  So unless you somehow have a way of maintaining the moisture level of your starting mix you will end up with differing moisture levels when you add the 8 oz of water to 5 cups of mix, correct?  In addition, depending on how dry the mix is when you subsequently water you will get a different moisture content when you add 8 oz.  I guess the main point of your post, as I understand it, is that once you get optimal soil moisture throughout the cup/SIP, you can then determine the weight. From then on whenever the mix needs watering you simply add water until you reach that weight and then stop.  Does this make sense?

I suppose the ultimate approach would be to have a soil moisture sensor in every cup and add water until you get to the level you want.

Rafaelissimmo,
Thanks.


Nycfig,
Thanks for commenting.
Getting the proper wick size in any planter was something I worked on years ago, after tests and comparisons to "successful commercial SIPs", the conclusion was that the wick should be 10% in cross section area of the planters cross section. It will work most of the time, with the recommended mix recipes. The custom potting mixes are the other problem, to be the most effective as wicks, the potting mixes have to be a high percentage peat or similar material. Before using any newly fabricated SIP, it should be tested with the planned potting mix for wicking ability and water distribution into a dry mix before planting. Also the only landscape fabric that I've found that will allow water to pass freely through it over time, is the Spun Fabric, the perforated fabric will quickly get clogged with silt.


Rewton,
No, its not usually bone dry, and you do not have to bake it, but it should be "almost dry", air drying a small amount is all that may be needed for a simple test. Most potting mixes are slightly "Damp" to the touch to start with and are much lighter in color, this would be the "Dry" starting point, and with a little experience, you can easily tell when they are dry. Typically you start off with a specific amount of mix, 1 or 2 cu ft bag or larger. the moisture level for that package will usually be uniform. Once you get the fill amount for your mix, it can be used consistently for that particular mix and specific container. Weighing the container will not actually work if the plant is actively growing, it will be adding root and leaf mass.

Its simply observing the plant and planter and adding the "Fill" amount or less when the plant needs to be watered, which will probably be less than a dozen times before the cutting's roots are hardened. Once the roots are hardened and the bottom has callused, the cutting will not be as sensitive to excess moisture.

I've been engaged in an off forum discussion about % water content of different mixes and the impact on successful fig cutting growth.

I thought I would share with the forum community a simple non technical explanation of the relationship of porosity, saturation zone (perched water) and container height. Al Tapla (Tapla) has commented and discussed these principles in the past, here and on GardenWeb. The application of these principles is the basis for the high success rates of the "New Baggie Method". By increasing porosity and planter height and eliminating the the saturation zone.

The saturation zone has been the cause of a large percentage of my cutting failures, excess moisture is held at the bottom of the container where it rots the end of the cuttings. This document provides simple explanations and procedures for increasing success rates. Although the subject of the article are plugs, it is completely applicable to growing out fig cuttings in small containers.
http://ohioline.osu.edu/hyg-fact/1000/1251.html

Quote:

 

The idea still persists that drainage from containers can be improved by adding a layer of coarse material, such as gravel, to the bottom of the container. In reality, this makes matters worse because the saturation layer is simply moved up, reducing the unsaturated portion of the container (Fig. 6).

Pete,

Thanks for sharing this. From what I gather from this article, although the author does not mention bottom-watering, it would seem that the mini-sips with air vent holes solve a lot of problems that top watering in small pots causes, regardless of the soil mixture one uses.

Milehighgirl,
You're welcome.
Yes Mini-SIPs solves some of the problems. They decrease compaction, increase aeration and lower the saturation zone.
But you still have to test your potting mix in your container and they have to be used within the constraints of their design they are not a panacea.

I do notice I have great root growth and little loss in 100% perlite filled cups for rooting (after bag method). After transplating to soil in 1 gallon pots and removing from humidity chamber is when I have most of my losses. Is this likely due to overwatering? 

Frank,
Its possible, but you have not provided enough information for a good guess. Usually the rooted cuttings are planted into the 1 gallon pots in the new "baggie method". Also once rooted the cuttings need less humidity and should be weaned off the humidity chamber as quickly as possible. In your description you write "soil" if its actual soil, there may be pathogens that will cause rotting of the cuttings, if there is excess moisture and the end hasn't callused. This document has some basic procedures to follow for ensuring high cutting survival rates.

http://www.flor.hrt.msu.edu/assets/Uploads/Sucessfullypropagatingcuttingstakesplanning.pdf

I don't know if this might help or not, but I saw a tester yesterday at WalMart that tests for soil dampness. I didn't read the whole package and I don't know how much it costs, or how it works, but it definitely piqued my interest. Think I might go back later and read the whole thing. I had 2 wee ones running around so I didn't have a lot of time :)

Jenn42,
You could try it and let us know how it works, but most moisture meters are not sensitive enough for measuring moisture for fig cuttings. They would register dry for the moisture levels that are required for good growth since very little moisture is needed in the initial growth stages.

I went back to WM this afternoon and it WAS a moisture meter. It was $10 & I thought "why not, I can always return it" so I did buy it.

I of course tried it out on some house plants I watered this morning & it read 7.9. So I then tried it on some cuttings I put in cups this morning & it read 2.1. Thats pretty sensitive since the cutting soil was moist and by no means saturated.

when I did my soil mix this morning it was moist (enough to hold a ball shape) but not wet.

I don't know if it would help anyone but it did read pretty good for what I tested.

I am by no means an expert, only a novice. I am in the same boat as others trying to not drown my cuttings. Just thought I would mention it because I had never seen one before.

I use 90% perlite with 10% seed starting mix. It is so light it is pretty easy to guess how moist it is and the water tends to run through really well. I also lost a lot of well rooted cuttings after taking them out of the humidity chamber. I have heard it called "sudden fig death". I only water once every 5 or 6 weeks, if that, when they are in the humidity box. When I do water I now use a product called Hormex, very dilute, in the water. It has almost completely stopped the "sudden fig death". I have also been told that feeding the cuttings can cause it, and compost can cause it. Something about the CO2 in the medium. When I up pot into gallon pots I continue to use a lot of perlite and then with each up pot I decrease it. But I always add a lot of perlite with anything that needs to drain well.

Jenn42,
Thanks for posting the update. What is the make and model of your moisture meter?
Your measurement is what I have found to be the case when used with fig cuttings, the readings are at the low end or unmeasurable when the cuttings are properly watered especially with coarse fast draining mixes.

Susan,
Thanks for commenting.
I don't use the humidity chamber for more than 2 weeks after the cuttings have been cupped. The chambers are not needed once the cuttings have rooted and if the temperatures are kept above 70 deg. F the roots will grow rapidly. I also start dilute liquid fertilizer (Miracle grow General purpose @ 1/2 teaspoon / gallon) as soon as roots have developed. From observations, Compost, Soil and Organic Fertilizers may introduce pathogens which will cause rot and attract or introduce Fungus Gnats, I start the cuttings off with as sterile a mix as possible. Solid organic fertilizers are added after the cuttings have been established in 1 gallon containers and the gallon containers are the same 5-1-1-1 mix as the larger containers, except that it has been sifted to remove the largest pieces of pine bark.

I'm using 100% perlite to sprout my cuttings. I have not experienced any "sudden deaths" after removing  the cuttings from the humidity chamber. I just started feeding my cuttings with a commercial grade 2 part hydroponic solution. If this works out as planned I will transplant them into soil after they have overgrown the pots with roots and I can move them out side (spring)

I'm using 100% compost. I use a regular 1Liter pot - The problem I have with cups is that the base is thinner than the top, and to me this means poor wicking  - just my idea .
I left the 3 cuttings (2 pots) in some home made humidity chambers - 1 was a clear plastic bag sealed over the pot in a reservoir filled with 2cm water, the second was a dark bucket sealed with a dark plastic bag with 1 cm water at the bottom.
After one month they did break bud (some water didn't get wicked), and I put them to the sun light - the days where cloudy to the most, and I changed them to a 30 W light tube close to my aquarium - So far so good .

Are you guys letting water stay at the bottom of the SIP ?
I watered yesterday (so far once a week, 0.5 cm of water in the plate under the pots ), and all the water disappeared in one hour ( the remaining water would be removed if necessary ).
Every two days I moist the leaves with a wick - It seems that my fig trees do like that - I do that to the ones in the ground - when they are growing not during the winter :) .

Rich,
Thanks for commenting.
The 100% perlite works fine for rooting from my experience. Transitioning to a potting mix is where the complications usually start.


Jdsfrance,
Thanks for commenting and sharing your procedure.
Good compost will probably work as long as its not wet. Leaving the pots in standing water usually invites rot at the bottom end of the cuttings, if they have not had time to callus.
From testing mini-SIPs, water should not be kept in the reservoir, and if the reservoir is continually filled the mix will get saturated and the cutting may rot. If you re-read post #1 you will see the simple procedure for watering, whether growing in mini-SIPs or regular planters. Please keep us updated on your progress.