Kitchen Garden Forum

Has anyone found a good guide to fertilizer applications for the various vegetables on the net or in a book.

I don't know whether its a negative influence of the organic movement, but i have yet to come across a definitive guide to veg plants nutrient desires. I feel to some extent there is a 'bury our heads in the sand' towards fertilzers whether organic or not within garden circles.

Indeed i am finding agicultural books from the 60's (that my uncle had) far more informative. though these are for large scale farming and rather difficult to re-calculate for the home garden.

This year i am going to try chicken manure pellets and seaweed meal for my potatoes. Can any one give me advice on how much i should use per square yard of the above fertilizers? I have given ground in autumn a dressing of FYM, but i would like advice on if i didn't as well.

when a packet of fertilzer has a NPK rating. Is this rating percentage composition by weight or by volume? For liquid feeds is the NPK rating once it has been diluted to normal strenght with water?

This is a very unscientific answer as I tend to fertilise by instinct rather than necessarily adhering to instructions on the packet. In autumn/spring I dig in a manure dressing on my veggie patch, and around mid July when I reckon some of the effects of that are wearing off or being leached out of the soil by regular rain or watering, I throw handfuls of chicken manure pellets over the areas where I have heavy feeders such as leeks, courgettes, beans, tomatoes, etc, but not on the root crops. Apart from years when we suffer really extreme weather conditions I find this works pretty well although I suspect some of the experts here will be pretty appalled by my practice !
I have to say, I find the manure pellets a very convenient way of adding nutrients. One summer I was given some extremely well rotted poultry manure which I dug in between the rows of my vegetable patch. My application coincided with a heatwave and the smell was so overpowering that it made me completely persona non grata with my two adjoining neighbours!

The only place I know that is definitive is the now out of print “Know and Grow Vegetables” written 1979 by people from the National Vegetable Research Station.

Here are some quotes with a scan of the main table.

Plant Foods and Feeding

Nitrogen

Fertilizers containing nitrogen are usually worked into the soil immediately before sowing, or applied partly at this time and partly mid-season top-dressing between the plants. The total amounts of a range of nitrogen fertilizers which can be applied to meet the needs of various vegetables are given in the Table. To find how much fertilizer to apply, first look on the bag and check the percentage N in the fertilizer. Then find in the Table, the percentage N which is closest to it and apply the amount appropriate for the crop you intend to grow. For example, broad beans will need 4ozs per square yard (136grams per square metre) of a fertilizer containing 5 per cent N but onlt 1½ozs per square yard (51grams per square metre) of one containing 15 per cent N.

Phosphate and Potassium

If your nitrogen fertilizer also contains about the same percentage of phosphate (P) and potassium (K) as of N (e.g. Growmore is 7:7:7) you will automatically apply enough phosphate and potassium along with the nitrogen.

In other parts of the book …

Farmyard manure varies widely in nutrient content but on average somewhat less than ¼ per cent N, ¼ per cent P and ½ per cent K.

Research has shown that organic sources of nitrogen such as blood and bone or fish meal produce no greater yields than equivalent amounts of inorganic fertilizers.




My personal, and I think practical, interpretation of this is that I feed the soil with as much organic matter as I can muster to get the texture right and assume it will contribute something to feeding the plants so I use slightly lower fertiliser quantities than the table, say about 75%. I tend to use some slow release organics as part of the feed for long season crops. I have found giving roots a P boost via super phosphate is beneficial on my soil (fairly light, very acidic, high rainfall). You could use a full NPK soil analysis if you are doubtful about you soil’s balance.

I have been doing a bit of study and maths regarding that chart from Geoff.

I also have a booklet from 1968 called 'soils and manures for vegetables' which was issued by the 'Ministry of Agriculture,fisheries and food'for the commercial sector.

lets look at geoffs chart first and make some calculations. i am going to do so in metric.

lets say we were using 'sulphate of ammonia' fertilizer which has a N value of 21. lets round this down to 20.

I am now going to calulate amount for early potatoes using geoffs chart:

2.25 x 34g = 76.5g

therefore we would use 76.5 g per metre squared. ie a big handful!?

Chicken manure pellets from 'Westland' only have a N of 4.5

therefore the amount needed would be roughly 4 times as much. which is 306g.

now a normal handful is 50g, therefore we need 6 handfuls approx of chicken manure per square metre. thats shit loads!!

So a 10kg tub of chicken manure pellets would only do 33 square metre patch. say a patch 4 metres x 8.25 metres.

On the tub of chicken manure pellets it says to use from 50g to 150g on vegetables. come back to that later

----------------------

Now lets go and have a look at my booklet 'soils and manures for vegetables'


this bit is a bit technical, and i only include it for those who wish to clarify.

Historically fertilizers npk values were calculated as units in a hundred weight [cwt].

[b] A unit of nutrient is one percent of one hundredweight.

eg: A fertilizer of 1-1-1 npk has 1 unit nitrogen, 1 unit of phosphate....



So take 'sulphate of ammonia' which has a N of roughly 20. therefore 1 cwt contains 20 units of nitrogen.

In the booklet they say that early potatoes should have 120 units of nitrogen per acre.

but 1 cwt of 'sulphate of ammonia' is equal to 50kg.

An Acre is 4047 square metres.

So 1cwt per acre is equal to 12.5g per metre squared.

if sulphate of ammonia has N of 20, then we need 6 times this to get 120 units.

6 x 12.5 = 76g

you probably will have difficulty following this, but if you look at the last figure, this corrolates to goeffs chart calculations for 'sulphate of ammonia'.

So goeffs chart does seem accurate with what the minsitry of agriculture said.

2 points though:
1)i have gleamed from the my booklet, that if FYM is spread in autunm, then we can reduce the units of fertilizer by 30 units. what this is basically saying to me is that the fym spreading is equilivant to 20g of sulphate of ammonia or 80g of chicken manure pellets or any fertilizer with a N value of 5.
2) you will see from goeffs chart that brussels sprouts etc require very high amounts of nitrogen. I feel the chart may miss lead us here. these figures seem to be the total dressing for period of plasnts growth. and from my reading of my booklet, the application of the amount should only be done in three stages. ie 50% before planting and 30%? during summer and 20%? prior to harvest time. ie i would be applying the calabrese, french bean chart amount at planting time.

So back to the spuds and chicken manure pellets.

they advise that if using this high amount of fertilizer/manure that scorch could be a problem, thus maybe 2 applications would be good here? or at leasts applying a few weeks in advance of sowing?

I have heard that spuds do well with high potash feeds particulary during tuber formation, so thats why i am interested in using seaweed dust or meal also.

personally i have given my spud plot about 2 handfuls of chicken manure pellets per square yard since i already put down fym earlier in autumn.

i do go along with the idea of using less fertilizers. But i still feel we bury our heads regarding the nutrient requirements of plants. i certanly do not suppert the offerings the organic sector used to supply to the whole food shopes 10 years ago. that was such a cod. they were just smaller,cause they were poorly grown. thankfully those days seem to behind us, and most home gardeners are producing much better vegetables.

Sometimes i find veg home gardening very disallusioning. i really feel like we in the darkness as regards plants and i hate the 'trial an error approach' that is common within circles. its quite hard to find concrete info.

i cant help comparing the state of veg growing and info, to that of the closet cannibis growers. these people put us to shame! they know so much more about there plants. 18 year olds talking about C02 levels, hybridisation, plant genetics, light spectrum etc. blow your mind stuff!!

wish we could be a bit more like them!!

Dear Dewwex, i think the biggest problem the average gardener would have is, unless they have there soil tested every Spring, they are unlikely to keep their soils to the ideal.
Some soils start a season higher in plant foods than others due to being covered in polythene, being uncovered and getting the nutrients leached from the soil, and different strengths of manure being added in the Autumn.

I must say that i do think a lot of soils run out of food for the plants before the growing season has finished though.

I do find all your calculations very interesting, and wish you well with your results.

i need to correct something i said.
i said the following statement in my last reply:

"On the tub of chicken manure pellets it says to use from 50g to 150g on vegetables".

On further looking at the tub, i find my statement is not correct.

it says 50g to 150g before sowing
while 100g to 300g before planting.

So i deduce as far as westlands are concerned 300g or 9oz can be applied before planting. which corralates to the leeks; potatoes (early) line in geoffs chart. cool. cause the ministry highest single application for any type of veg is the same. hopefully i am getting to the bottom of my original question.

In reply to oldherbaceous:
yes i agree there are a lot of variables.
i just had a look in my booklet again. they also give fertilizer rates for highly fertile soils. in the case of early potatoes this is 90 units of N. this calculated out is 225g of chicken manure pellets.

its quite an interesting booklet because with some veg they give up 3 differents depending on soil fertilty.

one thing i would like add. alot of the time in home gardening with talk about 'feeding the soil' and getting the general fertilty up. Now i know that fertilty is not really just about npk levels, more to do with soil structure and humus levels.

But at the same time what is the point of fertile soil? fertile soil for one plant is not fertile for another!

if we just focus on nitrogen,and look at goeffs chart we can see the demands for nitrogen for various veg differ enormously.

if we compared say thyme to the cucumber, the soil fertilty differs on every level one could say.
thyme wants to grow on poor soil (unfertile).

In most publications off the bookstore shelf the only reference to fertilizer amounts one comes across is the general 70g of growmore before planting normally. At times it looks very much like head in the sand stuff to me!

i realise that home gardening is a casual hobby for most. And alot of poeple want general easy advice.

But there is also a massive dropout level amongst gardening, and i wonder could the reason for this be lack of good information plus crop failure. gardening takes quite a bit physical of effort, and it can be very disheartning for prople who spend a few months trying to grow, for them to have a large portion of failure!

i am veg gardening for the last 3 years. i do a large range of plants, but i have to say, i am not really happy with my knowledge of gardening. And sadddely i find good info hard to come by. A young friend gave me a cannibas growing book to check out, and i have to admit, after a weekend read, i probably knew more about cannibas than any of my veg after 3 years. So recently i have been drawn to commercial booklets on veg growing! still not as good as the cannibas book!

anyway, enough of that, i think i got issues!! i will turn this post into an Agony Aunt column if i don't stop

but final rant:
A big thumb down to all the seed companys in general! 'Unwins' particulary, for putting growing instructions on packets which can be clearly wrong or shoddy.

your nothing more than 'seed sorting houses'

Very flattered you keep calling it "Geoff's chart" but don't forget I sourced it from a very reputable scientific organisation - National Vegetable Research Station - probably why your Ministry of Agriculture figures come out the same, probably the same research basis.
I had worked out that not only are chicken pellets four times the price of Growmore per unit of Nitrogen they also provide less P and K.
Beware considering big N donors like Sulphate of Ammonia without noting that you are expected to keep the NPK about equal.
However, when all is said and done, most veg has a habit of growing whatever we do to it that is why there are so many different opinions to keep the forum alive!

in reply to geoff:
yes i personnally wary of using concentrated fertilizers such as 'sulphate of ammonia'. Actually i have been growing organically for the most part. occasionally i might have used inorganic liquid feeds on say my tomatoes in my polytunnel, but in the garden i have been purely organic for the last three years. i was only using sulpahte of ammonia really as a reference point as the ministry of agriculture does most of its calculations by this basis, though they not saying to use such particulary. they go into blending other less concentrated fertliser quite a bit. the booklet was published in 1968, interesting from a cost perspective, that Hoof-and horn cost 8 times more than 'sulphate of ammonia' per unit of nitrogen back then. Also most of the inorganic fertilisers had a subsidy attached while the organic ones didn't. chemical company fingers at work??

speaking of costs, heres something that may interest you.

westlands have two products for tomato growing. 'Tomato Concentrated Plant Food' which is inorganic tomato food, and 'Organic Tomato & Vegetable Plant Food' for the organic growers.

both come in 1 litre bottles for about the same price.

'Tomato Concentrated Plant Food' has a npk rating of 3.9-2.6-7.7 but will make 150 litres of liquid feed

but the 'Organic Tomato & Vegetable Plant Food'has a npk rating of 4-2-6 but will only make 81 litres.

i got this info from their web site.
www.gardenhealth.com

but its interesting that on the bottles there is no reference to this! indeed they just say add 1 capful per gallon of water. they don't tell us how much is in a cap full. the capfuls must be different sizes??. Sounds like a bit of economy with the truth!! little bit deceitful for my liking?.

the other thing you will notice is that the npk rating of the organic is the roughly the same as the inorganic one.
so how is npk of liquid feeds worked out does anyone know? it must be when it is diluted to normal strenght? how would one calculate the equivelent volume tomatoe food in terms of N to chicken manure pellets.
my quick preassumtion calculations would be that 12.5 g of chicken manure pellets would yield about the same amount of nitrogen as 1 litre of diluted tomato food. lets not forget though the release rate may be quite different! indeed i have heard organic people say that organic fertilizers such as manure in fact release more nitrogen than on the packet long term, due to the humus content feeding nitrogen producing bacteria in the soil. inorganic fertilizers they would say could have a negative impact on soil bacteria, and earth worm population. though if you ever throw a bit of 'fish , blood and bone meal' on a worm, they sure don't like it either!!

just a point goeff. you say that we are 'expected to keep the NPK about equal'. Is this statement really true? If we look into it, i think we willl find that the different ratios within npk for various plant needs is quite different. but i not trying to be nit picking with you, i think we understand each what each has said. just making a point.

And bye the way, thanks a million for the chart. the more info we can get the more one can cross reference.funny how yours came from 1979 and my booklet 1968..emm!

good point goeff about the chicken manure pellets not been balanced. i get the drift. they are basically more a high nitrogen feed. But i think nitrogen leachs out of soil more than p or K. am i right? i am looking to use sea weed dust, particulary to boost K plus trace elements. though according to my booklet the application for potatos is a balanced application. heres hoping i have a enough P. oh god!!

i have read elswhere that potatos like high amounts of K. have you come across this info?

All this talk is just getting a bit too technical for me( and I suspect for most contributors also. What is wrong with good old Gromore. I think people are, as in many walks of life making the job of growing veg much too complicated. what do other people think?
Regards Brenjon

ya. sorry, maybe this tread is getting to complicated. though i personally find veg gardening complicated because the info is not out there! i feel there is quite a 'hush hush' aproach to the subject of fertilizers. And since we all generally have to use them, i find it disappointing that info on actual rates hard to come by!

I grateful to geoff, i think that chart is good, and i do feel now i have a better understanding of the application rates. sorry to other forum users, but i have used this post as kind of a study platform!

I have to say I found your posts very interesting, Dewwex, and I applaud your search for knowledge! The book "Know and Grow Vegetables" by P.J.Salter, J.K.A.Bleasdale, and Others (the source of Geoff's table) was recommended on this forum by John some time ago. Though it's out of print, it's readily available on Amazon as a secondhand buy. Apparently, there's a "Complete" version but I haven't seen that. I bought it in two volumes of which the first (ISBN 0-19-857547-5)is much the more useful imo.That's a paperback, by the way, and at between £3 and £5 is an excellent buy, I think. I've a lot of gardening books and it's one of the very best. The authors are members of staff of the National Vegetable Research Station, Warwickshire.
Good luck!

Iain.

I was reading through this post again. And for the life of me i couldn't understand how i came to calculate that:

'my quick preassumtion calculations would be that 12.5 g of chicken manure pellets would yield about the same amount of nitrogen as 1 litre of diluted tomato food'.

Even confused my-self.

So i wrote to the 'Garden doctor' at Westlands,via http://www.gardenhealth.com/index.php to get to the bottom of how lquid feeds npk was worked out and how much chicken manure pellets would be equvilent to tomato food in terms on N.

Here is their reply:

"The NPK labels on garden fertilizers are complicated, the current legislation means that we have to use the same labeling as agricultural products which does not help, although this is under review and may be changed in the future.



The NPK declarations on the products refer to the concentration as sold in the bottle. So for the liquid feed this is the weight of NPK per liter e.g 4:2:6, when you dilute the product the NPK ratio stays the same but the concentration is reduced by the dilution rate.



For the chicken pellets the NPK is 4.5 for N with a recommendation to apply 100-300 gms/m2. To apply approximately the same N level (4.0 Vs 4.5) for example if you were to apply 100 gms of pellets per m2 then you would need to apply 100 mls of the liquid concentrate to 1 m2. To do this you would need a watering can with a good rose fitting and I normally expect a 4.5 litre watering can to cover 10 m2, so that you could calculate from that. Say you want to water 10 m2 then pour in one bottle of the liquid feed and make up to 4.5 litres and water this onto 10 m2 and alongside it apply 1 Kg of pellets to 10 m2 and you have approximately the same N rate per m2.



Liquid feeding containers is slightly different as you are treating a volume of compost of media that is why the feeding instruction usually refer to a concentration rather than by the M2."

So my '12.5 g of chicken manure pellets would yield about the same amount of nitrogen as 1 litre of diluted tomato food' looks correct. phew!!

A few things to note:
1 litre of water weighs 1kg. So water based solutions can easily be converted from weight to volume.

A cap full of westlands 'Organic Tomato & Vegetable Plant Food' holds 50 ml of concentrate. or 50g of concentrate. A capful is added to 4.5 litres of water. thus you can see how 12.5 g of chicken manure is equivelent to 1 litre of diluted tomato food, or indeed, 12.5ml of concentrated tomato food.

A capful of 'Organic Tomato & Vegetable Plant Food' is equal to a normal handful of chicken manure pellets in terms of N.

Hope someone can benifit from all this apart from me. Again, sorry to all those who i have confused!!

I will try to get to the bottom of the differences between westlands two types of tomato foods and the cap size issue later.

Blimey!! what a lot of chatter for very little !! I havent really understood much of it. My view is that give your rows a little sprinkle of Growmore before planting does the trick for me I think we all get a bit hung up over what is organic and what isnt-to me growmore isnt anything that isnt produced naturally -hope I havent lit the blue touch paper here!?

In reply to bottomleypots:

"I havent lit the blue touch paper here"

But it does look to me that you are 'web-trolling', and if you did take the patience to read, you would see that the posts are not about organic verses non-organic debate.