Fertilization will vary depending on where you are and how your season runs, and how ready your plants are to produce. Most plants that are in healthy soil won't need much fertilizer.

When starting seed and developing my plants to plant out, I use a good soil mixture and rarely add fertilizer. Once in a while, if the plants are looking a bit stressed, I will occasionally lightly fertilize my starter plants using a light, liquid fertilizer mixed with water, but truly the starter seeds never need more than a single application of 1 - 1 - 1, and I generally don't even do that. I start my seed in February and plant out from mid-March to early May (using Walls of Water for protection). Our last frost date is sometimes in late April, but May 10th is almost always beyond our last frost date.

Once my tomatoes are in the ground I generally fertilize with small amounts of standard, quick release, balanced fertilizer, such as 8-8-8 or 16-16-16, throwing out a small, scant handful to cover a group of about 8 plants. I might do this every one to three weeks. While they are still in Walls of Water, I make no attempt to put any fertilizer in with the plants, but throw it on the ground around and between the Walls of Water, until I remove the WOWs on about May 15th.

I NEVER fertilize after June 1st. That is my cut off date, because in years when I have fertilized later, I always get massive growth of healthy vines, and FEWER tomatoes. Around June 1st is when about half of my tomato plants will be setting at least a few blossoms, so I guess this indicates I DON'T fertilize after blossom set starts.

Yes, I am DEFINITELY of the opinion that over fertilization or LATE fertilization causes too much vine growth and actually delays production of the fruit that we want.

Our killing frost date is generally around early-mid October. If I over fertilize, my plants grow happily right up to frost without seeming to make the shift to significant production.

DETERMINATE plants might not be as sensitive to the effect of too much fertilizer (or for too long), since they are genetically programed to make a shift to production at a certain time, but I grow few Determinates. Like most home gardeners, my plants are almost all Indeterminates.

Fertilizer might also not have as much fruit delay effect on certain CHERRY TOMATOES (like Sungold and Sweet 100s), because they set so much fruit anyway, but one season, when I fertilized my cherry tomatoes all summer long, I got vines that were nearly 20 feet long. So I don't fertilize them much, because who needs vines that big?

I use fish emulsion and tomato tone once a month, it is good stuff.

I don't always fertilize depending on how much amending I did to the soil the previous year. When I do I mix 6-24-24 into the planting hole and throw on a little more the last time I hill them up. I think this is a good choice for tomatoes, not so much N but plenty of P and K for fruit production.

In the link below scroll down to the discussions with the blue bands around them - at least 50 discussions on fertilizing, which fertilizers to use, when and how much to apply, etc.

In other words there is no one answer that applies to all. A very general guideline is feed just after first fruit set and then approximately every 6 weeks. But that all depends on how well amended your soil is, how often you have to water, whether you use synthetics or organics, how you apply it, whether you use granular or liquids, how long your growing season is, etc. etc. etc.

If your raised bed is peat and compost then it has no active soil food web, no micro herd, to convert the compost to a useable nutrient form. Compost is primarily a soil amendment, not a fertilizer anyway so yes you will have to feed them something sometime.

Personally I use fertigation with my drip irrigation system in my in-ground beds so my plants are fed a very diluted dose of liquid organics every time they are watered. That plus lots of compost worked into the soil over many years and an active soil bacterial herd is all my plants need.

Your needs will be very different.

Dave

Here is a link that might be useful: Fertilizer discussions

Short of pulling soil samples throughout the season and taking leaf samples for analysis you are never going to have a highly reliable guide for fertilizing your plants- Don't laugh; quite a few professionals are suggesting just that.

What I've learned in listening to what some of those people have learned is that the plants do become deficient in certain nutrients as the season progresses. I use drip fertigation like Dave and I typically will start adding Calcium Nitrate in the system soon after I start picking. I've been picking so I better get moving. I did apply a foliar spray of Calcium and Potassium (K) already since one researcher noted that he could not supply enough K into plants by fertilizer alone in his tomato trials. You'll never be able to supply the ideal combination of all nutrients but as long as you are in the ballpark you'll have a great crop.

My uncle was watering his tomatoes with a compost tea made with chicken manure every time he watered and wondered why he never got that many tomatoes. I don't fertilize once I set out the transplants, just always made sure the soil was good by amending it each year and testing before planting, but I'm wondering now if I should fertilize. Once it stops raining and I need to water, that is. We've had 4" of rain just since Friday, and another 4 expected today/tonight.

While I got my plants out late due to 3" of rain Memorial Day weekend and a heat wave the last 2 days of May and 1st of June, I wonder if the nutrients will have been depleted (and the pH lowered?) with 12" of rain in 3 weeks. Time for another soil test (and maybe replacing plants though so far they don't look diseased) once things dry out a bit?

Thanks for the responses. Sounds like most don't fertilize much (the operative word being much). I have done the MG thing in past years where I got the most beautiful, leafy plants and not many tomatoes. Seems like the culprit here is too much N. Also seeing lots of discussions about what exactly is organic? Haven't been able to arrive at any definite conclusions about this.

I wonder if the nutrients will have been depleted (and the pH lowered?) with 12" of rain in 3 weeks.

Very likely.

Also seeing lots of discussions about what exactly is organic?

Natural ingredients vs. synthetic ingredients like Miracle Grow.

Dave

Excellent discussions and view points. I Think "fcivish" has a good analysis that I agree with. When you have a limited ripening season there is no point in keeping fertilizing for ever, ESPECIALLY, when you have a rich well established garden soil. I would even further expand on "fcivish"'s reasoning and say that , I would even discourage and prevent any new growth(blossoms branchings) a month to six weeks before the expected first frost date and let the plants ripen what already they have in green stage.

I also do sort of "fertigation", manually. I use liquid ferts (14-14-14) once a week or so, at 1/3 recommended strength, on tomatoes.

I fought this for years and here is where it lead me.
Using synthetics can and will produce more as well as more dependable results 100% of the time IF you know exactly what you are doing. That means if you don't hold a degree in the field,it will be hit and miss even asking questions of people who hold the degrees and know exactly what they are doing. Problem is the expert must see and touch the plant,know history of soil&run fingers through it and know precisly what has been done including but not limited to,daily weather,amts & timing of water and nutrents up to that point.
Organic is the way to go for even for the most dedicated gardeners. Organic is more forgiving of neglect and mistakes eventhough the mistakes and neglect will reduce production,it's not intolerable amounts. Non-organic mistakes often result in drastic results up to and including 100% loss. An often incountered one is where fertilizer is applied then miscalculation of weather and/or moisture occurs. Another is where insectiside is used to rid a pest that is effecting a plant by eating leaves or sucking some juice but not killing it nor ruining all fruit. Benificials on neighboring plant is eradicated and a pest that was being kept in check or shows up suddenly mushrons and ruins one or more crops. Very few things you do organicly will result in such sweeping results,good or bad. The soil should always be in transition for the lack of a better term.
This addresses fertilize applications. In any container or plot , I try to insure there are diverse types and stages of finished compost. That insures that as micros are consumed replacements are being produced. I believe far too much gravity is afforded N being tied up by deterioating matter. Dumping a lot of fresh material like saw dust with huge amounts of exposed surface will definitly starve plants until rate of decomposition slows. A case where there is negitive results but usualy recovers enough to produce a fair to poor crop. Turning under green cover like vetch can realy supply season long crop fuel. I just cannot stress enough how important it is to understand your plants and that will happen with experience and experience will come sooner by asking inteligent questions of those willing to help. In an effort of convincing sceptics that it is possiable to read plants,I offer some off topic evidence. Try this out if you know a rancher,not nessarly an old crusty one, a cowperson in their 20s is quite capiable. Drive him/her to a herd they have never been around and without leaving the seat of the vehicle they can tell you;
very near the age,the sex,weight and breed/mixture of breed for each animal while average person is deciding what color they are. If alowed to walk near them (many cattle dislike and will run away from strangers) closly estimate stage of pregnancy while our novice wonders why the one giving birth within a week is not fat as the one who has 3 months to go. Think about human faces. Isn't it amazing that we can differinate all of them. Practice!

Klem1,
I honor the concept of education but totally disagree with your assertion that the use of synthetic fertilizer will have hit or miss results if one does not have a degree in the field.
Experience counts for a lot, and I appreciate those who share theirs here (and I appreciate you sharing your conclusions even though I disagree with some of them).
My own experience is that I have had a satisfactory return from my gardening efforts and I do not use all organic, I buy fertilizer and use it judiciously.
I do like the idea of replenishing the soil with organic matter but think that there is no one-size-fits-all method with the diverse weather and soil conditions that the many readers throughout the U.S. and the world encounter.

This addresses fertilize applications. In any container or plot

Sorry but even the most devoted practitioner of organic gardening acknowledges that strict organic gardening, what you have detailed above, does not work in containers as it does in-ground.

Dave

I agree with Dave. I mostly container grow, and fertilizing regularly is crucial to the health and production of the plants.

At one time, our tomato garden was icky clay, but over the years, I built it up with amendments to make it loamy. We've had great success growing tomatoes here, however last year, I was unable to properly compost our plants. The tomatoes flourished anyway into big leafy plants, but there was very little fruit. I attributed it to the high temperatures in SE Wisconsin over last summer.

This year, I used compost and it has been a cool, wet season so far. Unfortunately, there are no blossoms yet, even on the Sweet 100's. The tomato plants are lush and green. I'm at a loss to figure this out. A neighbor suggested tomato spikes to fertilize, but I'm reluctant at this stage. Any ideas on what I should do?

Don't fertilize. If the plants are "lush and green" it sounds like they're already getting more than enough nitrogen to keep them happy, so they don't feel the need to reproduce (see my post above about my uncle using chicken manure tea and wondering why not that much fruit).

I don't know what/when you've been using to amend your clay, but clay will hold onto water and nutrients longer than sandy loam like I have, just wait it out this year and have the soil tested before you amend any more in the fall (or next spring), even with compost.

so real question will be if I have lush and green plants but very few tomatoes- I can see evidence of having plenty of nitrogen and except of keep taking the soil for testing, is there evidence that we might have low P and K numbers or nitrogen needs are overriding everything else and we might have plenty of P and K but it is not being used? And since it might be hard to lower N level except by leaching it out by repeated watering, what else can be done to balance?

P and K just don't get depleted/leached as much as N, and P is something you don't want to add if it's not necessary so it's best not to fertilize with anything until/unless a soil test indicates it's necessary.

Now, I did have a situation this year when with all the rain the N got leached to very low levels, but the plants were showing mainly P deficiency symptoms, which I knew wasn't right. The roots just weren't growing well with the constant wet (though sandy soil drains well) and the plants weren't able to take up the P that was there. Once it dried out a bit (and I did do 1 foliar feed with fish emulsion) the roots were able to grow and the plants established themselves, they are looking great now though smaller than I would expect for a month in the ground (they stalled for a couple of weeks).

I have never heard of anyone *trying* to decrease the N present in their soil. Just don't add more. I suppose if you want to "use it up quickly" you could try throwing in some kind of leafy green as a companion to your tomatoes. But I think that just normal watering/rain would work - have patience, don't flood your plants just trying to wash the N out (not like containers that you're trying to leach salts out of).