I've been growing passiflora foetida hydroponically. Successfully I must say, and in my case the plants were pretty easy to grow and quite forgiving. I used small buckets filled with coco husk chips in a drip and recycle system. The formula I used was low in nitrogen compared to potassium and low in concentration. It's a plant that can grow under harsh conditions, in poor soils and shouldn't get too much nitrogen and a lower concentration as usual on top of that.

PS: other species or varieties may have different requirements - this is specific observation and conclusions about passiflora foetida.

Here is a link that might be useful: passiflora foetida

Thanks lucas_formulas, "small buckets", so 12 litre (3.2 gallons) buckets would be fine? You think Passion Fruit would suit DWC?

Hi again,
Passiflora foetida is a in fact a ranking plant not a bush, and I used small buckets of only 2.5 liter. For other species (varieties) a 12 liter bucket should do the deal at least for the first year and beyond.

I am also growing mountain figs, Neem (Azadirachta indica), moringa and some others. They grow in rather small buckets or even in shallow gravel beds of only a few centimeters for now and doing amazingly well. Most trees and bushes are (at least seem) very adaptatif and forgiving. I am keeping nutrient levels low, between 1.2 and 1.4 only- and low nitrogen levels versus fair Mg, Ca, S and generous K. Not sure if you can adopt your nutrients accordingly, but those are my results so far.

Not sure about DWC only. But I was thinking of a hybrid system as they grow bigger. In fact the same drip and recycle bucket system with a DWC reservoir under the bucket. As soon as the roots grow out of the buckets (around 8-10 liter) they would be placed on top of a "open" DWC reservoir and could expand their root system in that way. This could be a underground DWC system. It could be realized with smaller (15-20 Liter) individual reservoirs for each bush, or a elongated trough that can hold several buckets (always on top). The actual DWC reservoir(s) would also be connected to a bigger reservoir, from where the content can be recycled a few times a day. Hence the individual (or common) reservoir would be fed by the dripper of the bucket system from top and there would be a outlet (of the DWC reservoir underneath) that would be connected to the main reservoir.

Just sharing my thoughts, not sure if it is an appropriate solution for everyone or for any case. But when planting bushes and small trees, you need to preview bigger growth and the consequences anyway.

Also note that (as I said) coco husk is fine, but decomposes (breaks down) over time and is actually only appropriate with short growing cycles (as with passiflora foetida). For a longer period a more inert media like a mix of pea gravel with perlite, granite split, vermiculite, etc. would be more appropriate and PH-safe.

Last but not least: don't forget to have or plan an adequate support for bushes, especially at windy locations!

They took forever to germinate and were really struggling with the heat over summer with lots of scorching and blistering (not sure what is causing this) but anyway since the weather has cooled down they are really taking off and a few flowers have appeared, my soil grown ones are not flowering and were sown at same time.

Decided to go with drip system.