Topic: Feeding Tomatoes

[Jayb]

For feeding toms this year I’ve some liquid Westland tomato (4-2-6) food to use up and then I’m going to use Chempak’s tomato food (11-9-30). I’ve always fed roughly weekly sometimes about every 10 days when I remember!  But Chempack’s instructions say to feed weekly for 1st and 2nd truss stage and then from the 3rd truss at every watering. I guess it’s not so economical after all? How often do you feed? Anyone else using Chempack? It's the first time I've used their tomato feed.

Also I’m growing a few tomato plants in pots resting on a tray with a container underneath acting as a reservoir via capillary matting. All feed and water will be supplied from the reservoir. Question is, how do I work out how much fertiliser to add up to the 3 truss stage so I’m not over feeding them? Is it then ok to just mix as the packet instructions, 2 level teaspoons in 10 litres of water?
Many thanks

[goodlife]

I haven't used chempak's feed...but if you are feeding with 'standing water reservoir' way..I would give 1/4 strength feed if you are going to provide the feed 'almost all the time'..half teaspoon for 10 litres of water.
It doesn't hurt to be very frugal with feed..you will soon see if they should need any more/stronger solution. If you have any liquid seaweed..add drop of that into weak feed solution and it will aid with the nutrients uptake, like a booster...that way weaker solution is working even better for you plants

[Jayb]

I was hoping to work out a ratio of feed to water in advance so I can just leave them to get on with it. But I’m afraid I haven’t a clue how to work it out.

[goodlife]

I'll have a look later on tonight if I can work out some ratio for you...thing is...I shall be needing it myself once the provided feed with planters run out.
It will give some work out for my little grey cells

[goodlife]

Ok...I have been doing some calculations and measurements 

The original fertilizers that comes with quadgrow planters ..one of the containers has 250g dry fertilizer (approx. 36 tsp) makes 830 litres of diluted solution... each tsp of dry stuff mixed with adequate amount of water works out as 23 litres of diluted stuff.
Now it gets less 'scientific'....I should not imagine that consentration of nutrients in dry 'stuff' vary huge amounts in domestic fertilizers.. so in that rate 1/2 tsp per 10 litres would be plenty in 'high' summer and like with quadgrow fertilizer..coming to late summer/autumn or in poor growing consentration of the rate should be reduced.
I would think that my original guess with chempak fertilizer...1/4-1/2 tsp of fertilizer per 10 litres of water is not far off what is needed. Any stronger than that and standing fertilizer solution near roots would risk damaging roots.
I would start with 1/4 tsp per 10 litres while the plants are still young and there is nutrients still in compost...increasing the consentration for 1/2 tsp for next fill up.

I hope I made sense...

[Ian Pearson]

I find feeding is not necessary if the plants have wide spacing, and the soil is well stoked up with organic matter and mulched. It would be interesting to do a comparative trial. Obviously container growing is a different matter.

[goodlife]

JAYB....don't rush to mix any feed yet..

What is the NPK ratio in the feed?
Is your champak feed the 'red' box or the 'blue' ..there is 2 different feeds that are suitable for tomatoes although the 'red' box is the 'proper' tomato feed. I could only find the ratio for the 'blue' and the consentration is VERY different to the original quadgrow feed.
AND...I measured the Quadgrow feed in heaped teaspoons....where as champak say 'level teaspoon'...so my guestimate won't be very accurate.
If you can let me know the NPK and I work it out again...

[Jayb]

Good points Ian, trouble is I'm forever trying to squeeze in another must grow variety of tomato, so my spacing ends being quite tight. I think if I were better prepared I'd certainly be able to reduce the feed I'm putting on, but after the last 12 months of wet my soil prep has been pretty basic I'm afraid.

Goodlife, NPK is in the first post. I'm using the Red box, standard tomato food.

[goodlife]

AH...I need  ....ingnore my PM....

[goodlife]

Ok...the comparison feed is 6-9-25...so very similar to the chempak's
I'll do my 'spooning' and calculations later on..must dash off to work for few hours and I'll get back to you with results..

[Jayb]

 

[Jayb]

I just looked on Greenhouse Sensations site, I think the stuff I had is 250g per 2.5lt before further diluting. But they have an A + B and I'm not sure what's in each?

[goodlife]

Right...work turn out to be no no.. it is very wet here... rainy day

Ok..with the guadgrow 'original fertilizer'..it works out 1tsp dry stuff=12.4 litres of final solution..BUT..they have fertilizer A and B that have to added into same reservoir..A is similar in contents as Chempak..B is 12-0-12+ calcium = 18-9-37+ calcium (that's to prevent blossom end rot) and yours is 11-9-30..

Whoooah..this is bit brain ticking stuff.. hmm...if there is no added calcium in the tomato feed..keep the ration slightly lower rate...you could do 1 tsp per 15 litres of water...it is still enough nutrients for good growth and particularly if you do have some liquid seaweed handy..5-10ml addition of that would do good..other option is to add bit of calcium to the feed, chempak sell some of that separate...but it needs adding to the diluted solution separately not mixed together as strait fertilizers. The trouble is that when you feed and water through reservoir..you are going more by the hydroponic rules rather than normal feeding rules and admittingly I'm not fully familiar with hydroponics. The nutrients are supplied in highly diluted form as if its too strong solution one nutrient can deplete others intake or even cause some physical damage..and then there is the 'carrier' difference with the different feeds for different growing mediums I suspect your planters will be filled with compost..
I don't think you are too far off if you use 1/2 tsp-1 tsp per 10-15 litres of water...play by the 'ear' and see what the plants tell you
That's best I can do...for now.. one option is to buy more of  the 'original' fertilizer for quadgrow planters..Greenhouse sensation do sell it separately from the planters, haven't looked what it cost though..

[galina]

4-2-6               Westland
11-9-30            Chempak

n-p-k ratios

The Westland numbers roughly multiplied by 5 gives the p and k numbers for the Chempak one.  They are very similar for p and k.

But the nitrogen (11 instead of 20 ie 4x5) is effectively only half strength with the Chempak fertiliser.

So you are comparing apples and pears to start with, which doesn't help.  However you are using them the right way round - higher nitrogen numbers in the Westland initially = good growth for the tomato plants.  And when you run out and the plants are more into flowering and fruiting, the Chempak is more suited and the tomatoes don't need a high nitrogen fertiliser anymore.

I cheat - comfrey liquid and chicken pellets applied as and when ......................      easy peasy

I agree with Ian, but you have to be far more diligent with pots than with well-prepared soil. 

Does this make sense?     

[Jayb]

Thanks both, I'll let you know how I get on. I've been a bit wary as it's for my toms for Jeannine's competition, also two of my favourites Pink Berkeley Tie Dye and Black and Brown Boar