On a similar note...Would you also recommend not tampering with plants if you've had shoots that grew out, quite well, some over a foot, and then simply died later? I gave them fertilizers and pot ash, etc, watered them regularly but not too much and kept them exposed to light, either natural or a plant bulb for 15 hours a day. Still, my Magnum died and my Cascade snapped at the base and died as a result. I figure if the roots are still growing, there's no point messing with them.
Be careful with the potash, and any other fertilizer. You can easily overfertilize and cause damage/death of the plant. A lot of ferts can really change the pH of the soil which can affect nutrient uptake and many are also high in salt. For potted plants I would not even recommend fertilizer (chemical that is), rather mix a good amount of organic material into the soil, such as partially composted materials, leaf matter, aged manure, etc. The environment in a pot is just so different that it doesn't take much to overfertilize. An alternative since you've already constructed the soil for the pot is to use 1:10 diluted plant food such as Tropica Master Grow or another all-in-one fertilizer. By 1:10 I mean whatever they recommend for tsp per gallon, cut that even more.
And on the same page overwatering is VERY easy in a pot due to moisture retention (walls of the pot behave as barriers and so it can keep the soil too wet). The most difficult time is waiting for them to get some roots established because frequent short waterings are required, but I'd ALWAYS suggest erring on the dry side. The other issue with watering a pot is the water TEMPERATURE. In a garden the soil temp will negate quite a temperature swing, but in an enclosed pot its much easier to shock the rhizome/roots. If your ambient temp is 65F, make sure the water you add is close to that. Easiest way is to set out the water you plan to use so it has time to acclimate to the right temperature. This also helps gas off chlorine if you tap has it (note: chloramine will not gas off), and normally increases dissolved oxygen into the water helping to keep the soil aerobic (most tap water has high dissolved CO2 but low O2).
If your one bine broke itself as you said (just lost turgor pressure and collapsed) that could be a sign of overfertilizing (or underwatering). I've started to give my bines some slight support when they are >4". A small twig an inch or two into the soil will give them something to climb on so they can focus on growth rather than rigidity. Once they get longer you can gently "re-train" them onto your larger support.
In my very short stint at hop growing I've noticed an unusual growth rate trend of the bines once trained. It seems like there might be some chemical/tactile signal that a bine produces as if to say, "Hey, I've got a vertical support, gimme more food!". While the other bines continue to grow slightly, the trained one becomes a cruise missle shooting up the support. For example I have a Cascade hop that's single trained bine is 3-4' (FEET) tall, while the other bines from this same plant are only ~6". I have done no pruning, just let them all grow and chose the strongest for training. My other 2 Cascade hops appear to be acting similarly.
So I think ASAP get the hop trained on something, even if you later remove the support from those first couple inches.
Not the greatest picture (and this was a couple weeks ago), but you can see how much taller the trained bine is:
