Planted Ponds

[colonel]

So its that time of year again, I live up north in Ohio so its just getting warm and thawing out, and im going to be helping my Dad out to get the spring cleaning done on his pond next week.

He just had a beautiful pond put in last year and he loves it, before that he played around with various small pre-formed liners, but they were to small to be stable and have more than a few Koi and it was always a battle with GW and other various algae for him. Non the less he has enjoyed it very much and last year decided to have a large pond put it.

It's about 1000 gallons, give or take a few.... and surprising since it gets full sun almost all day long it ran great last year with no real algae issue other than in the stream, there was a good amount of string algae that would collect there but for some reason it would never grow in the pond its self...... though there was a decent amound of brown algae covering the rocks in the pond thats all there was.... the water stayed very clear and it was a pleasure to enjoy through the summer.

Now for my question, part of the filtration includes the water fall box that is ment to be filled with water Hyacinth and it was obvious that after a few weeks they began to wither away badly, im sure from lack of many nutrients as nothing was added to feed the plants other from fish waste.

There are several other types of marginal type plants with roots that feed from the water, along with lillies and I am going to buy him a large assortment of "weedy" type pond hearty stem plants to include also.

Is there any good way to go about adding ferts to such a type of pond? It is a Koi pond so there will be tons of fish waste probably a lot of PO4, and a decent amount of NO3 I would assume K+ would be at the top of the list of things to add... along with traces.

Also something to take into consideration is that with the pond being in full sun most of the day, there is a good deal of evaperation and it is getting topped off a few times a week, so there is probably going to be a build up of Ca and Mg.... unless of course the plants are really moving along quick and sucking that stuff out.

Welp thats all for now, if more information is needed please let me know.... I know Tom has expierence with this sort of thing but I would also really like to hear from others who have ponds too

Thanks!
~Matt

 

[Tom Barr]

Re: Planted Ponds

I would suggest adding floating plants like Hyacinth, pennywort, water lettuce etc.
50% or so coverage will prevent any algae related issues.
You can also add Egeria densa, or hornwort etc
Add lilies but fertilize the pots.

If the plants are warm enough, higher than say 50F during the coldest nights, they should do okay.

If the plants die off, then add more KNO3/KH2PO4.
Not a lot, but watch the plants.

As the weeds grow, they will take up much more nutrients.
So responding to that will be the main focus.

I've never had to add ferts to most ponds/lakes, they were already fairly mature and had enough mulm and waste accumulated.

I dount you will need much traces, CMS might be a better solution,cheaper etc.

I would only dose once a week at most and run on the leaner side.

Plant 30-50% of the surface with Emergent aquatics, rushes, cattails, Horsetails(twisted etc), lilis, irises, etc, then the remainder with a floating aquatic like Hyacinth.

The rest of the bottom area, fill in with Egeria and/or hornwort etc.

Now you will need to go in every 2-4 weeks and harvest the excess plant growth, make sure that is done, other wise it will be worse for the fish if you have too much plant biomass.

That should do it.

Keeping ponds clear is easy using weeds.
I always laugh a bit at pond owners obsessiveness with algae cures.
The 20-30 or so ponds/lakes I've helped folks with all got the same type of advice and have not had algae related issues since.
Some have had a mild bloom once or twice a year but it went away in 1-2 weeks.

Use the plants to keep the water clean, it'll do better than all the filtering and UV stuff you throw at it.

Regards,
Tom Barr

 

[colonel]

Re: Planted Ponds

Thanks Tom, we really didnt really have any algae issues last year that were enough to be a head ach. I was more or less thinking about what will the plants need for thier health, because last year they really didnt do well at all. We had good coverage last year... but after a few weeks the plants just sort of died back and were weak, not making much of an attempt to flourish at all.

like you mentioned.... I doubt KH2PO4/KNO3 will really be needed as I am sure there will be plenty from the Koi. Maybe a bit of CSM once a week to target maybe .1 ppm iron? What about K? is that an issue? something that should be added lightly once a week or so also? Thanks

 

[Tom Barr]

Re: Planted Ponds

Well, these systems tend to be slower responding.

The Koi do add some nutrients but it's virtually always N preferenced.
The P and K are lacking in most fish waste.

you'll also note how things grew well for a little while, as the plant biomass increases, so does the uptake rate, you have a lot more biomass and it's all happy and acclimated.

Now you can do a few things here.

Harvest when the plants appear to be slowing their growth, or add more plants/allow thenm to grow in more, and add more ferts.

Do not assume you are getting enough NO3 from the Koi either.

If you triple of quadruple the plant biomass, it'll(NO3) often drop pretty quick on a hot summer day as these weeds need no extra CO2.........

I think P and K will limit growth first though.

But beyond that, then you can end up limiting NO3 if you add everything else but that............

It'll take either some a good test kits or simply watch and playing around with getting to know your weeds well enough to know when to add P, K, or NO3.

You can add K+ from K2SO4 without much issue, so you can rule out K+ easy enough.

PO4 the same but at a 7:1 atomic ratio(K+ atoms, not mass-convert the ratio to mass => 39.1 x 7 / 30.97 = 8.8-9:1 by mass K) with the K2SO4.
Same type of thing with Traces.

I would add only once a week and note the plant's health.

Large water changes are often impractical at these scales, so dose on the low side.

Some have found using a limiting rotation can help and also teach you what to look for, you need to pay attention to subtle effect on the plant growth and not rush to judgement too fast.

Basically you limit say NO3, by adding P, K, traces.
Then after the plants start to slow their growth, you add NO3, anmd stop adding say K+ this time, wait till you see negative growth signs.
Then add the K+ back and then move to PO4, you will see slowed growth, but not like the other two. Then you can try traces later, these tend to take longer time frames to see issues, then it's hard to say which trace is limiting first..........

So either havest and maintain less plant biomass, or add some ferts to maintain more plant biomass.



Regards,
Tom Barr

 

[colonel]

Re: Planted Ponds

Thanks Tom, that is very helpful... Since I dont currently have good test kits, and it isnt in the plan to get any soon I will just have to go by watching the plants. Which will be good anyway because I could use more practice getting to know how different plants respond to limiting nutrients, or addition of nutrients.