Could you please define, "too much compost"?
It's just not within my realm of experience to make a finite judgement, you're going to have to develop your own experience level. What I'm trying to get across about SIPs fundamentally really is that the problem of water stops being about dealing with its scarcity, which really many horticulture practises are developed to combat, but instead your dealing with the potential always existing of too much water getting into the matrix. This is why the airgap is so fundamental and why, as I also hope to also get across, I believe that Azimuth's point that this air gap is the critical factor is not in conflict with my overall belief that SIP success is a function of a more efficient root system unburdened by flood and drought scenarios constantly taking place.
There simply is a threat of root rot and root drowning in SIPs and the use of aeration, and keeping an eye on moisture-holding amendments like compost, are all ways to ensure that over the many, many days your plant's roots are in proximity to this much water, the critical oxygenation levels are maintained. Lots of successful SIP grows with lots of compost have taken place, lots of SIP grows with little to no aeration have taken place, however, I think it is pretty clear from reading everything possible to find on grower SIP experience, that the primary threat is loss of oxygenation and subsequent root rot as the root fails. Because SIP root systems appear to be reduced in mass given above-ground plant size when compared to other container grow styles, it is hard to not come to the conclusion that there is an efficiency advantage inherent in SIP-type growing. The notion of no longer needing to grow the largest most robust root system possible is going to take an awful lot of evidence behind it for most growers to come around, and considering the fact that its been accepted as axiomatic by growers for decades I'm not sure its even possible in the short term. But, as with any complex system that's been around long enough to have matured and already been streamlined, it is developing new efficiencies which ultimately give you success when competing against other complex systems.
So when I say to have this much of that or this, I'm just reaching for what I believe offers you a reasonable safety margin. Yeah the air gap is key, and it's key because the wicking mechanism will proceed unchecked long past 'field capacity', ie will take on more moisture than is healthy for the plant, thus it needs to be countered. Soil is capable of holding much more moisture than is healthy for our plants so we need to build in safety features, features that will permit the plant to live without the experiences of drought and flood we've been pushing on them as a method of protecting them from 'user error' (over or under watering which is going to happen eventually if you have no way of really knowing what conditions are deep in the soil).
Leveraging the air gap's critical contribution by avoiding heavy moisture-holding soil mixes and utilizing a large aeration percentage simply puts you and keeps you in that ideal zone for the plant over more levels of "reservoir fullness", and will permit you to use the reservoir's level as a tool for managing the type of growth you want to see take place at any given moment. I think having an over-moist soil type will force the grower instead to have to keep her reservoir less full in order to manage against possible over-wetness instead of being able to utilize the entire range of her SIPs capacity at any and all times for whatever the scenario that warrants addressing. A fuller rez means a wetter soil in SIPs. So you want a totally full SIP to be a useable state of things just like you do a near empty one, so that the entire range is available to you as a tool for management.
phew.
You lock your car doors at the end of summer, so people don't give you too many.
The gringuito is funny!
when I fertigate from above, the plants don't seem to use much of the rez the next day so that might be a strategy you could use to extend the period by a day to deal with your father.
Sounds like a plan, Buds. Don't overdo it though. Your plant's hydrotropic root development ought to be well enough along by now to not be threatened by a single top watering.
All my threads are in my sig!
