# Making a terrestrial foliar feed from Tropica premium



## Simon Cole (28 May 2020)

Hello my friends,

I have been working with organic composts this year, and I have diagnosed a immobile micro-nutrient deficiency across a polytunnel.
The problem is due to an incredibly high phosphorous load recorded in the compost and plant tissue. This has bound up one of the immobile nutrients in the soil but we are not sure which one. The head gardener used bat poo. I have leached most of the phosphate out now, and I dosed with calcium and magnesium (also as foliar application):  It made no difference. I am therefore confident through the power of deduction that it will be something like Zn or S. The mix also contained a lot of peat so we don't have an ideal buffering capacity.

I cannot find a decent trace mix locally and Royal Mail are consistently taking up to two weeks to deliver 1st class post where we are working, never less than 7 days. The only thing we could get hold of was Tropica premium, which looked ideal to make into a foliar spray.

I have read in places that foliar sprays need to be several times the concentration of root feeds. I know that aquatic fertilisers like Tropica can be a little bit light.

Any recommendations for the dilution factor?
Also, how long does that stuff last on a shop shelf?

- It is a clear bottle and must have been exposed to UV - which I know is bad for iron stability - what about Zn, Mg and S?

Glad that this post is a little bit off piste for once


----------



## jaypeecee (28 May 2020)

Hi @Simon Cole 

Good to 'see' you again. I can't answer your question but if I mention @dw1305 right here, he may get a notification. I seem to recall that Darrel has worked in commercial horticulture in the past.

JPC


----------



## Simon Cole (28 May 2020)

Thanks John. I was going to ask Darrel but I'm always impressed by the knowledge shared by the society, I guessed he might be quite busy teaching. Fingers crossed.


----------



## LondonDragon (28 May 2020)

@Mick.Dk might be able to shed some light also


----------



## Simon Cole (29 May 2020)

Fingers crossed for Mick too 
I know it is a very difficult question - not many people on my team knew - I will ask tomorrow next door at the organic gardens. I think they want it all to be organic, so I don't know how I'm going to get around this one. I just cannot face the uncertainly of using seaweed extract compared to what we aquarists do. Organic aquarium fertilisers = now that I would call unfeasible.


----------



## PARAGUAY (29 May 2020)

Also they may help TNC drop a email


----------



## dw1305 (29 May 2020)

Hi all,





jaypeecee said:


> I seem to recall that Darrel has worked in commercial horticulture in the past.


I did, <"but a long time ago">.





Simon Cole said:


> ...I guessed he might be quite busy teaching.


Last week of (virtual) term, so busy with a lot of meetings. 





Simon Cole said:


> I'm always impressed by the knowledge shared by the society


I have a pretty _laissez faire_ attitude towards fertilisers and fertilising, but we have a lot of members who have approached it in a much more scientific and rigorous manner.





Simon Cole said:


> I have leached most of the phosphate out now


My guess is that it will still be a large reservoir of PO4, it is really strongly bound to humus and clay, and <"difficult to remove">


Simon Cole said:


> The head gardener used bat poo.


I think that makes a micro-nutrient deficiency more unlikely, insects are pretty rich in most micro-elements  and <"so is bat guano">.





Simon Cole said:


> I have read in places that foliar sprays need to be several times the concentration of root feeds


Usually the same fertiliser rate as you would use <"for liquid feed">.





Simon Cole said:


> The only thing we could get hold of was Tropica premium, which looked ideal to make into a foliar spray.


Should be fine, it will be  a bit light on nitrogen.

Personally I would go down the <"Miracle-Gro route">, at ~£5 for kilogram you re going to get a lot more <"bang for your buck">.

cheers Darrel


----------



## Simon Cole (30 May 2020)

Bingo - slight chance now that we have the culprit. I will anticipate S deficiency - not in bat poo. That was in the polytunnel with a better vapour-pressure deficit (VPD). If this fails then it's phosphate leaching time  
On a side note, the other tunnel had very low humidity (poor VPD) and we have all the classic signs of nutrient issues. They built the darn thing with net sides so it makes leaf-nutrient control almost impossible. 
Cheers Darrel. All those years of your research have paid off. Hopefully you have helped to feed the "community" down on the project right in the middle of lock-down. Thank you.


----------



## Simon Cole (2 Jun 2020)

I think I've cracked it. All of the plants are recovering after using a slightly elevated dose of Tropica Premium as foliar feed and root irrigation. Unlike other formulas it includes both S and Mg. Seems to be an ideal quick fix.

I also noticed that this cheap kit off ebay  looks largely identical to  Solufeed Sodium Free TEC™ and they have dosing instructions for all types of irrigation systems, including foliar. I'm not sure what the optimal dosing of trace elements would be for different aquatic plants, and I cannot find any info about this within the EI framework, but I suspect that trace element optimisation could be the key to growing certain more problematic aquatic species.


----------

