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High PK fertilizer- when and how to use

Posted by plantslayer (My Page) on
Tue, Jan 27, 09 at 22:29


After browsing through old posts on this forum, it seems that people generally like to provide their tomatoes with high phosphorus and potassium fertilizer, but take it easy on the nitrogen.

In my garden we have a lot of fishmeal at our disposal, which I think is something like 6% Nitrogen but no more than 2% P and K. Also I've got field peas as a cover crop that will be turned under a few weeks before tomatoes are transferred to ground, and a fair amount of composted plant material.

So I think the plants will have plenty of nitrogen between the fish meal, cover crops, and liberal use of compost. Supposedly the soil around these parts is often deficient in P and K, however. Since I am required to use organic fertilizer, I was thinking about getting some Neptune's Harvest 0-10-10 concentrated organic liquid fertilizer, and simply watering the plants every few weeks with this stuff diluted as per instructions. Is this a good hassle-free way to provide my tomatoes with the P&K they need? Has anyone used it for tomatoes before? Will it make the soil too acid if I am not careful?

Also- do you think that the Neptune's 0-10-10 stuff would help seedlings out if diluted according to instructions, or perhaps even more diluted?

Advice is appreciated, as always!

Follow-Up Postings:

RE: High PK fertilizer- when and how to use

HI, I'm no expert but I think you should fertilize about a month after you plant withe The Neptune 0-10-10 and then right before the plants start to ripen lots of fruit water them with sea kelp for the micro nutrients. Thats at least what I would do around here tomato fertlilizer when the blossoms appear and sea kelp when the fruit start to turn pink.

Hope this helps and that it's not all wrong.

RE: High PK fertilizer- when and how to use

I'm curious, how does it come to pass that you are "recquired" to use organic fertilizer?

RE: High PK fertilizer- when and how to use

Larry, Plantslayer may be certified organic or just have personal reasons but regardless you should try to mix most of your P & K into the media/soil prior to the final planting. Unlike Nitrogen those nutrients move through the soil slowly and much may not get to the plant root zone. Many potted flower growers are using slow release coated fretilizer for that reason- so that those nutrients are in the root zone when the plants need them most.

RE: High PK fertilizer- when and how to use

I'm required to use organic because I garden in a community plot, and predictably the people that organize these kinds of things are true believes in organic gardening- accordingly they have rules about what kinds of fertilizers and pest control we can use. Personally I am not a organic growing zealot (I know that a lot of farmers make perfectly good produce that doesn't meet organic produce standards, and often find it hard to sell at farmer's markets around the US now), but I would say that works well for tiny plots like mine. I don't think it costs me more than a few dollars per year more for fertilizer (and some effort working on compost) than it would otherwise. Being in the city, pests are probably not quite as bad as they would be out in the sticks, and my area is so small I can weed entirely by hand. :)

RE: High PK fertilizer- when and how to use

I appreciate your reply.

I will use whatever I can get each year in organic soil suppliments; mushroom manure, well rotted horse or even cow manure, etc.

But it is hard to get at a reasonable price around here and much more is needed than I can get. So I pretty much must suppliment with chemical fertilizers.

I will probably use some 8-32-16 in my garden this spring.


RE: High PK fertilizer- when and how to use

I think this is already implied by the other comments, but is it correct that you don't really want to feed the seedling extra phosphorus or potassium before it transplants (and then only after it starts to bloom)?

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