[mikew4895]

Hi

my dad has a Koi pond and he's draining it soon. He said the water would be good for my veg. Does anybody know whether this is true and whether it will benefit the plants in anyway?
I have tomatos, courgettes, peppers, lettuce, carrot,, cucumber, beetroot, onion, sprouts.  
The tap water were I live is very limey too

Cheers
Mike

[Trillium]

the pond water might be a tad high in nitrogen (fish manure) but otherwise it should be okay for your veg plants. You might want to keep an eye open for water snails and use a bit of screening on the drainage hose.

[sunshineband]

As Trillium said, it'll be just fine.

We use the pond water and fish tank water with no ill effects

[JayG]

Water from aquaria or fish ponds is good as it normally contains more nutrients than tap water, but not so much as to cause any problems for established plants.

As with collected rainwater, to be on the safe side I don't use it on very young seedlings as it's likely to contain quite a high population of mould and fungus spores.

[rcf100]

the pond water might be a tad high in nitrogen (fish manure) but otherwise it should be okay for your veg plants. You might want to keep an eye open for water snails and use a bit of screening on the drainage hose.

The pond water shouldn't be high in nitrogen if there is fish stock currently using it.  About 6 weeks after introducing the fish there should be bacteria breaking down the ammonia, nitrates and nitrites otherwise the levels would become too high and kill the fish.

There's actually a method of growing both fish and plants together called aquaponics where you create an Eco system where the fish water feeds and waters the plants and the plants feed and filter the water for the fish, if you use the soil technique rather than a hydroponics technique.  It's something that we are looking to set up once we have our extension done.  Fresh fish as well as veggie.  It's a technique becoming popular particularly in the far east and slowly growing in popularity over in the west.

[mikew4895]

brilliant. thanks for the advice. ill make sure i screen it too just incase there are any snails inside. 

[Dr_Pepper]

Nitrate is the form in which (most) plants take up nitrogen, so the nitrate in your pond water is unlikely to do your plants any harm if the fish are happy. If you have a lot of aquatic plants in the pond there's probably not much nitrate in the water anyway. Other things like phosphates will be good for the veg patch too.
As for aquaponics rcf100, here's a pic of a small goldfish/lettuce recirculating system I rigged up at uni a few years ago:

[Alastair-I]

The pond water shouldn't be high in nitrogen if there is fish stock currently using it.  About 6 weeks after introducing the fish there should be bacteria breaking down the ammonia, nitrates and nitrites otherwise the levels would become too high and kill the fish.

Ammonia -> Nitrite -> Nitrate are all aerobic bacterialogical processes.

Nitrate -> Nitrogen is anaerobic and unlikely to be occuring with any degree of efficiency in a  typical pond filtration system (unless there is a specific anaerobic filter block).  I would be surpised if your dad didn't measure the nitrate concentration with a test kit, maybe he can tell you this measurement?

If there is a reedbed or other vegetable filtration in the system then direct take-up of ammonia or nitrate by plants can be effective if the vegetation is removed from the system.  It can be so efficient that a lightly stocked but heavily planted aquarium can have lower nitrates than the water coming out of the tap.

I would expect typical pondwater to contain measurable but low levels of nitrates and phosphates.  Water snails are unlikely to be a threat to terrestrial plants, but might cause a problem if you're keeping a rice paddy.

Before using it I would check with your dad if he has recently added any treatments or medications to the pond - serious koi keepers do have a habit of dosing the water (sometimes off-label) with algaecides, wormers, pesticides to control parasites, etc.

[rcf100]

As for aquaponics rcf100, here's a pic of a small goldfish/lettuce recirculating system I rigged up at uni a few years ago:

Looks good, how did it work out? Did you do a control test with growing from rain/tap water?

Step 1 in our aquaponics was our greenhouse, had that a couple of months now. Step 2 is electric to it, will happen in a few months when extension for a up, step 3 hubby getting all the kit in place for the fish as he's a fish keeping nut.  Hopefully in 2 yr time we will be self sufficient on electric, off grid for gas, have a nice fish stock and a supplement of veggie from the garden. One can dream!

[jay.mox]

As for aquaponics rcf100, here's a pic of a small goldfish/lettuce recirculating system I rigged up at uni a few years ago:

Looks good, how did it work out? Did you do a control test with growing from rain/tap water?

Step 1 in our aquaponics was our greenhouse, had that a couple of months now. Step 2 is electric to it, will happen in a few months when extension for a up, step 3 hubby getting all the kit in place for the fish as he's a fish keeping nut.  Hopefully in 2 yr time we will be self sufficient on electric, off grid for gas, have a nice fish stock and a supplement of veggie from the garden. One can dream!

This sounded great, was there any good news to share?
I am quite into the aquaponics at the moment too, i have a small 250 liter system in the shed now, i am overwintering the fish and trying to get some peppers and tomatoes through as much of winter as i can.   The plan now is to integrate my wife's idea of a wooden deck wrapping around the shed and my idea of a 2000 liter+ aquaponics system with trout tank/pond. 
'the landscaping project' should be complete by Feb hopefully!