Ideally, you should use a fertilizer with a 3:1:2 ratio, as that has been established to be the ratio in which most plants take up nutrients regardless of their stage of life. The notion you have to bump up P to encourage flowering and/or fruiting is much more a fertilizer marketing gimmick than it is a fact of gardening life. P is rarely lacking in most soils anyway.

Without knowing what's in your soil, it's difficult to recommend optimal fertilizers. My soil is very high in P and K. I've got the numbers. Adding more would be silly. I top dress with a mostly N fertilizer, since N is easily leached, and everyone is happy with that. I guess if you start out with soil that is known to be very nutrient deficient, like soilless mix, getting numbers right on fertilizer might be smart.

Yes, go with a fertilizer higher in nitrogen. Way too much N will give you lots of leaves without a corresponding increase in fruit, but most soil has enough P, and a slightly higher N level will keep your plant green.

Tomato plants require different ratios at different stages of growth and are much different than a flower or vegetative bush. The most abundant nutrient used by a tomato plant is potassium and makes up 40% of the mineral composition, and Nitrogen is 25%. A big percentage of K is used in the fruit and makes up about 60% of the mineral composition and nitrogen is 30%.

In the vegetative stage a NPK ratio of 1-2-1 is a little better than a 1-1-1 ratio but still OK.

The NPK ratio for tomatoes in the flowering through fruit set to fruit growth generally is 3-2-5 with another application into the fruit growth stage. For mid to late season applications P can be omitted entirely with a NPK ratio of 1-0-2.

What about your calcium and magnesium? Calcium should be applied about 1/2 to 3/4 of the phosphorus used by weight. Magnesium applications should be around 1/2 of the Calcium used.

So a NPK+Ca+Mg ratio would be 3-2-5-1-0.5.

I'm not out to confuse you but because you referred to plant stages I'm assuming you know a thing or two about tomato plants. Now this is optional but if you are able to increase the ratio of nitrate to ammonium for your nitrogen source you can reduce nitrogen acidfication of the root zone and improve nutrient uptake for healthier plants and better tasting tomatoes. This article can better explain how Different forms of nitrogen are not the same and how PH around the root zone can change. If to much Ammonium is applied the PH can drop as low as 3 and stay there for a good week and to low for the plant to take up most nutrients. I use potassium nitrate to balance the nitrogen but there are fertilizers which do it for you and list a nitrate as a source of nitrogen.

"Tomato plants require different ratios at different stages of growth and are much different than a flower or vegetative bush."

Exactly how and why are they different? They are a flowering plant that produces an edible fruit, just like scores of other flowering and fruiting plants. They require nothing any more specific wrt fertilization than does any other flowering and fruiting plant! The notion that they some how require this exotic fertilizer regime is just buying into a mystique that some growers like to foster, much the same as rose growers do.

It's rather amazing how well much of the world can grow tomatoes - or roses for that matter - without adopting these complicated and wholly unnecessary phased fertilizing programs! To be honest, the only time I bother to fertilize anything is when it is grown in a container and has no access to nutrients other than what I provide. Inground plants in a decently fertile soil (like a vegetable garden routinely amended with compost or aged manure) rarely require any supplementation.

i have grown Ts for a hundred and 50 years ... and never once did i fert them ... and i grew them in sand ..

and usually by august.. i have so many i cant pay people to take them ...

dont make this harder than need be ...

a little of this or that will be good enough..

you can make it rocket science ... but you dont need to ...

a hobby is a hobby.. so have fun.. no matter what you do ...

and if you have multiple plants ... just leave on untreated all season.. and let us know how different it all works out ...

btw ... adding foo foo MG marketing mumbo jumbo soil to the planting hole.. many not have been a wise use of money ... per the logic above ...

ken

Your ratio will grow tomatoes gardengal, I also agree organic supplements will grow tomatoes and have no problems with what you do or advise others to do. But I work to produce perfect fruit without blossom rot, yellow shoulder, catfacing and other preventable problems through proper nutrition, and of course amazing tasting tomatoes. And I'm sorry but your way just doesn't work for me to obtain results I want, and my advised ratios and applications come from science through decades of study.

Tomatoes are in the top 4 of vegetables grown in the U.S. and because of their importance the research has never stopped. 50 years of scientific study is overwhelming and available to support my ratios coming from people and institutions devoted to the subject, not just me. A rose plant doesn't produce 20 to 80 lbs of mineral rich fruit like a tomato plant does and requires different ratios and amounts of readily available nutrient when needed. They also don't require more of a nutrient in excess then needed, and becomes counterproductive.

Science had proven a ratio of 3-1-2 is excessive in nitrogen for tomatoes, which causes problems and deficient in potassium which also causes more problems. Their work also shows to property fertilize a crop would require over 100 lbs of cow manure for every 100 square feet, and the NPK amounts and ratio is much higher in nitrogen than potassium which will vary widely between sources, so best used for grains without adding additional potassium. Vegetables, including tomatoes need more Potassium than manure can supply for quality and productivity. To supply the nitrogen for a tomato plant from manure you would have a K deficiency, and to provide the potassium they need you'd end up hauling 200 lbs cow manure per 100 sq. ft. and have excess N, with excessive foliage and lesser and smaller fruit plagued with issues in deformity and disease.

If I used manure I'd defiantly supplement with potassium and what they did 100's of years ago in Europe. To get the potassium they cut down 1/2 the trees to burn and to make "POT ASH" from the ashes. Your way works but so does mine backed by science, and I don't need to haul 1000 lbs of manure just for my tomatoes.

Most of the "science" behind growing tomatoes is intended for commercial production and is really unnecessary for home gardeners to adhere to in any kind of devoted following. Unless they have more time and money on their hands than good sense.

With more than 40 years experience of growing tomatoes and generating bountiful, healthy harvests, it is patently obvious to me (and scores of other home gardeners) that tomatoes can be grown perfectly well in ordinary fertile and well drained garden soil without needing to resort to some complicated phased fertilizer regime.

If you want to go to all that trouble, fine, but it is totally unnecessary!

Why does it bother you what I do? I'm the one who decides what I do is necessary and see no reason why you should even care. I have no problem if you stick a plant in a pile of manure and watch it grow, and if your happy with what you get good for you. If you've been doing it the same way for 40 years you've learned nothing new and know nothing more than when you first started. That isn't experience, its repetition and without knowing or caring why it grows. Hey, and if it's how you want to do it for the next 40 years go for it.

Now I prefer to give advice based on the advancement of science from people who have real experience and what I'm practicing now, and not what I knew 25 yrs ago, which is nothing. The NPK ratio in the flowering to bulking stage is 3-2-5 and proven by science and practiced by commercial growers worldwide. I'm not going to dumb it down because someone is a home gardener, who I think want the same or better results as a commercial grower.