Backyard Aquaponics
A place to discuss aquaponics

My AP system is coming into its first summer and I've been planting out dwarf bean seeds and cucumbers in both the seed and seedling forms. All the seeds have germinated beautifully but get to a point when they shoot their first mature leaves and then it shrivels up and stops growing. I suspect it may be salt (which is at 2.4ppt) or pH around 8 which might be doing it. Or is that beans and cucumbers just hate having wet feet? Can anyone shed any light please or suggest a varieties that prosper in an AP system?

My cucumbers are going amazingly well... I have probably a dozen small cucumbers growing so I dont think its a wet feet issue. We started from seedling.

Do you have a system thread or some pictures and a description of how your system works?
If the beds they are in, flood and drain and you are not flooding above the surface of the media, then wet feet is probably not the problem.

The pH of 8 could be a problem especially for the cucumbers. I've had very poor luck with cucumbers during my first year when I pH stayed above 7.6 and I wasn't adding much in the way of Iron or maxicrop.

I would add some chelated Iron and seaweed extract when planting the next time. Cucumbers can be very sensitive if they don't have Iron available through the seedling stage.

I have the same problem with my climbing beans, and I think pumkpin (at least I think they are).... the leaves are similar to the cucumbers, etc I think. Anyways, my climbing beans started off with some green leaves, and then now there is only small beans (2cm) hanging off the stem with all the leaves dried up... I think this happened when I had to increase my salt content from 1ppt to 3ppt... Cucumbers in another system at about 1ppt seems to be growing... slowly though, but the leaves do not dry up and die...

Would really like to know if it is really the salt as I would not be replanting the beans until I can drop the salt content to about 1ppt again...

Well its a 6 bed flood and drain system which doesn't flood above the media. I noticed in the topic of best plants in AP systems (I noticed it as I posted this question) it states that butter beans are a successful variety. I assume that most AP systems are salted between 1-3ppt so not sure what I am doing wrong.

Butter beans are going great for me. From seed they grew very quickly and producing beans. Purple climbers shot out of the ground at the same time and have grown well but very slow at producing beans.

Cucumbers that I planted from seed are doing very little. Actually still the two leaf stage I think and they were planted at the same time as the beans.

I don't think the salt would be affecting the cucumber plants but the high pH could be a real problem for them since they seriously need Iron while young and high pH locks out Iron.

I don't know if salt is a problem for beans though. I don't remember them being listed as extra sensitive to salt and many people run salt up to 3 ppt regularly. Strawberries are the only ones I know that might have trouble with salt levels that low.

LJC....recent proof over here that high levels of +8ppt salt kills staws, cucumber (lebonese), watermelon and climbing beans (snow). Had to salt for fish disease as an extreme case and watched late seedlings mentioned above mostly wither away within hours.

However @ 2.4ppt I don't think its salt as pH at 8 wont help.... take a close look at your bean leaves as could be phosphorus def

181. Dwarf Bean Plants
Phosphorus deficiency Growth dwarfed and thin: leaves dark, lustreless green, older leaves turn brown and shed early. http://www.hbci.com/~wenonah/min-def/beans.htm


At 8ppt cucs and straws have mostly died but snow peas and passionfruit still doing well so maybe cucs from salt but if beans could handle 8 sure they could thrive in 2.4

In my system both cucumbers and beans do not like salt much over 1ppt. Both will start to grow but look weak and sickly then stall and die.

I'm having the same problem. I planted cucumber, beans and pumpkin. They seem to germinate then slowly die. I tried using seedlings and within a few weeks I had the same outcome. Only one cucumber out of about 15 has survived and that looks nice and healthy. My beans germinated quickly and grew about 15 cm and turned yellow. They only produced a couple of beans each. I salted my tank to 1ppt when I first got barra and haven't added any since. I have no idea what is going wrong.

I have no salt in my system currently and have been experimenting with banana peels.

ph 7.4.

I dn't know what the optimal ph is for cucs, but 7.4 seems to be going well for me.

here are some pics of my cucs.

I ran a high PH for a while until a week ago. My cucumbers had surged ahead once the PH got around the 7ish.

Cucumbers like PH 6 - 7.
They are one of the more fussy plants.

I would imagine that over time if you can get them to grow even if it is just one, that the seed collected from these plants will be more suited to aquaponic systems. Over time there should be more plants suited to these conditions( eg higher salt levels) , just has been done with dirt plants, aquaponics is relativley new still.

We've been getting that many cucumbers that I have started pickling them. I noticed today about another 5 or 6 on the go as well.