Fertilizing during fruiting

alamo5000May 2, 2010

I have always 'heard' that you should not fertilize a tomato plant when it gets to the fruiting stage.

The reasoning is 'the plant will put too much energy into producing more greenery and not enough into making fruit'...

At least thats the reason they told me....

I do not see any real reason to believe this...but I thought I would ask to see...do you fertilize once fruit is set on the plant or no?

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wordwiz

As a kid, we grew several tomato plants, usually a couple hundred at a time. Dad never fertilized them except as "side-dressing" the plant with ammonia nitrate (33-0-0) when the plant was about 14" tall. We always had a fantastic harvest.

My guess is he did this because his dad did, and his dad did because his dad did, etc.

Same thing with potatoes. He claimed that would cause the tubers to retain too much moisture and make them softer.

YMMV,

Mike

    Bookmark   May 2, 2010 at 3:02PM
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bigbubbacain(z9a TX)

I guess it depends on your N-P-K numbers. When my are fruiting, I still spray them with Monty's 2-15-15. The P helps the plant to continue producing blooms. The K helps with fruit development and ripening. I don't think 2% N is too much. I still had a great crop doing this last year.

    Bookmark   May 2, 2010 at 4:35PM
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spiced_ham(z5 OH)

You will increase the likelyhood of blossom end rot if you boost growth at the time of flowering (it diverts calcium away from the fruits to the growing leaves). That is one reason many commercial growers wait and side dress with fertilizer after fruit set.

    Bookmark   May 2, 2010 at 5:18PM
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taz6122(N.W. AR.6b)

Fertilizing with high nitrates is the wrong thing to do but as bbc states above they could use a boost in P&K with very little N. More K than P.

    Bookmark   May 2, 2010 at 9:05PM
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engineeredgarden(7, nw Alabama)

alamo - you should side dress with a high nitrogen fertilizer when the first fruit reaches 1-1/2" in diameter. I think a tablespoon of 33-0-0 is recommended for each plant.

EG

    Bookmark   May 2, 2010 at 10:48PM
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az_pamperedchef(9)

I'm a complete tomato growing novice. I have 9 plants in various stages, all heirlooms. Just today I watered them all with "Miracle Gro". Did I do something wrong? Espcially since some of the plants already have 'maters on them?

    Bookmark   May 3, 2010 at 12:50AM
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tdscpa(z5 NWKS)

I think fertilizing without knowing what your garden needs is doing something wrong.

Fertilizer is getting expensive enough that cost alone should warrant having your soil tested before applying fertilizer it may not need or could even be harmful.

    Bookmark   May 3, 2010 at 6:17AM
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HoosierCheroKee(IN6)

I tend to agree with EngineeredGarden. Our information from Purdue Extension Service and Ohio State Extension Service advises a side dressing of high nitrogen at first fruit set. So, I've followed that advice for 3 years now, since taking their Master Gardener course, by side dosing a little palmful of granular 10-10-10 or high nitrogen lawn fertilizer (whatever I have available in the shed) for each indeterminate vine when I see the first truss of thimble-size green fruit. It's worked well for me.

Some folks who experience excessive foliage on their tomato vines may want to leaf prune to kick their plants back into "phosphorus mode" and thereby stimulate more flower production. I do this by snipping off the outer 1/3 of several leaf fronds or wholesale stripping off some of the excess foliage of the more aggressive vines.

    Bookmark   May 3, 2010 at 7:04AM
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engineeredgarden(7, nw Alabama)

hoosiercherokee - I guess you're the first to agree with anything i've said in this forum - even acknowledge that information i've given is useful, for that matter. Thank you.

I mix 13-0-13 and gardentone 3-4-4 (50/50) into the soil at the time of planting, which gives an overall NPK value of 8-2-8.5 - and sidedress with nitrate of soda (16-0-0)once the first fruit is 1-1/2" in diameter, and repeat every 4-6 weeks thereafter. I also went through the Master Gardener program, and tend to follow the recommendations set forth by the agricultural colleges.

EG

    Bookmark   May 3, 2010 at 9:16AM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

do you fertilize once fruit is set on the plant or no?

Yes, but with in-ground plants I wait till just after the first fruit set. I side dress each with fresh compost and blood meal mixed and once most plants in the row have first fruit set I add some liquid fert to the fertigation set-up via the soaker hose or drip line.

Container plants of course are already on a regular feeding schedule with watering.

Dave

    Bookmark   May 3, 2010 at 9:24AM
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HoosierCheroKee(IN6)

"hoosiercherokee - I guess you're the first to agree with anything i've said in this forum - even acknowledge that information i've given is useful, for that matter. Thank you." [EngineeredGarden]

EG, I agree with other information you have given in this forum as well. It's just that after participating here for 5 or 6 years, one learns to pick one's issues more and more carefully. There's a lot of information offered here by folks repeating myths and non-personal anecdotal advice. Just the way it is. Science and mythology often runs along conflicting routes.

But if you've employed methods proven to work for you, please continue to post information that could help other tomato growers.

Side note: I've learned a lot about nutrient requirements for tomato vines from a friend who is a commercial hoophouse grower using 24/7 fertigation. As you know from Master Gardener training, we aren't qualified or allowed to give advice to commercial growers; so, I just listen to them when they offer experience or guidance. There are a few commercial growers who visit this forum occasionally with some very good information. Timmy comes to mind. There are a couple of others.

    Bookmark   May 3, 2010 at 9:41AM
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engineeredgarden(7, nw Alabama)

hoosiercherokee - thanks again. I agree, sometimes it's best to just remain quiet on some subjects, but it gets to be difficult at times.
Fertigation is something that i've looked into, but it isn't something that i'll likely do for my situation. Viable information comes from many sources, and most of mine has came from over 400 gardening books in my personal library, as well as the Alabama Cooperative Extension System. However, I do listen to all people's input in this forum, because everyone has something to contribute.

EG

    Bookmark   May 3, 2010 at 11:15AM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Viable information comes from many sources

Very true. And there isn't just one right way to do anything - including growing tomatoes. All any of us can do is relate what has worked well for us and encourage others to experiment in their own gardening situation to determine what works best for them while trying to help them avoid the more common pitfalls.

But I do have to add that our Master Gardener program from the University of Arkansas tries to focus on guidelines specific to growers in Arkansas rather than establishing how-to guidelines that may or may not be applicable in other parts of the country and the unique growing conditions there.

So we need to be careful with what we slap the label "mythology" on. It may just be a differing opinion. ;)

Dave

    Bookmark   May 3, 2010 at 2:02PM
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HoosierCheroKee(IN6)

So, Dave, what does the Arkansas Master Gardener program or the University of Arkansas Extension Service recommend regarding fertilizing tomato vines?

I know the University of Arkansas says this about commercial tomato growers: "Most growers use a complete fertilizer disced into the soil at planting. Lime is used to avoid blossom end rot, and they lime according to soil test results. They will follow up with a high nitrogen fertilizer two or three times during the season, depending on the year."

But what recommendations does your state extension servive/MG program give for home gardeners to follow when fertilizing tomatoes?

    Bookmark   May 3, 2010 at 2:33PM
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engineeredgarden(7, nw Alabama)

Dave - yep, growing a tomato in the deep south is much different than one in the Pacific Northwest. As i'm sure you've experienced, it gets pretty ugly down here during July/August. I personally enjoy learning from others in this forum, but am hesitant to respond most of the time. The reason is because of hostility reserved for anyone that challenges the methods or ideas of some of the more prominent posters of this forum - as well as those that hang onto every single word or picture that they would submit in a thread.

EG

    Bookmark   May 3, 2010 at 2:44PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

So, Dave, what does the Arkansas Master Gardener program or the University of Arkansas Extension Service recommend regarding fertilizing tomato vines?

Like you we don't do any commercial consulting so most of our calls are the home gardener with anywhere from 2-25 plants. We are supposed to evaluate each garden and each plant independently rather than make any blanket recommendations.

That said, as a general guideline we are taught to "side-dress with a nitrogen fertilizer such as ammonium nitrate at the rate of 1 tablespoon per plant after the first tomatoes have grown to the size of golf balls. Then make two more applications three and six weeks later." That's when I do my fertigation.

If the gardener wants to be strictly organic both blood meal and alfalfa meal are considered acceptable substitutes. And anyone who can't or don't want to do a fertigation-type feeding can just side dress again.

Prior to planting prep is "fertilize with a complete fertilizer at the rate of 3 pounds per 100 feet of row. Apply 8 ounces of a starter fertilizer solution (1 tablespoon of 20-20-20 per gallon) when transplanting." And we have "organic substitutes" list for that too.

As to the lime, it depends on locale in the state. South part of the state, yes often needs lime but the north central is already very alkaline soil - heavy in limestone here - so we often have to acidify instead and the eastern part is more like river bottom. Since AR has so many diverse regions, geographically, U AR puts out a good series of county-specific gardening guidelines.

Dave

Here is a link that might be useful: U AR Tomato Growing Guidelines

    Bookmark   May 3, 2010 at 5:03PM
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HoosierCheroKee(IN6)

Thanks, Dave. Good stuff.

BTW, I love pink Arkansas tomatoes. Bradley, Traveler and Indian Stripe are among my favorites.

    Bookmark   May 3, 2010 at 5:54PM
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roper2008 (7b)

What is nitrate of soda? Is that the high nitogen fertilzer. I have some
garden tone, bloodmeal, Scott's 10-10-10. Should I side dress the 1"
tomatoes with the bloodmeal or 10-10-10. What fertilizer brand would
have 13-0-13?

Linda

    Bookmark   May 3, 2010 at 9:26PM
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engineeredgarden(7, nw Alabama)

Linda,

Nitrate of soda is a rock mineral fertilizer that is 16% nitrogen by volume. It has no Phosphorous or Potassium, and will raise the ph of soils, too. Since I live in an area that receives lots of rainfall each year, lime must be added on most years anyway. Phosphorous gets bound up into the soil, and Potassium too, to an extent. So, nitrogen is pretty much all I add once the plants have fruitset.

EG

    Bookmark   May 3, 2010 at 10:16PM
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tracydr(9b)

Is the fertilizer schedule different for indeterminate types vs determinates? I mean, it makes sense to go by the size of fruit/first fruit set if they all set fruit at the same time but if they continue to blossom and set fruit all season how does that work?
Also, I have some sea kelp solution, bought it because my plants looked stressed. Does this add any nutrients besides micronutrients? I understand that it's very good for the roots and plants, just wondering if it's adding anything in the way of NPK?

    Bookmark   May 4, 2010 at 3:17PM
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digdirt2(6b-7a No.Cent. AR HZ8 Sun-35)

Is the fertilizer schedule different for indeterminate types vs determinates?

Not really it is just that indeterminates will need additional feedings. 3 weeks and then 6 weeks after the first etc. as I said above is what I recommend - averages out to approx. once a month through the growing season. But that will be affected to a degree by the type of fertilizer you use each time - liquid vs. granular vs. timed-release. And of course this is in-ground plants we are talking about. Container plants have a very different schedule for feeding.

I have some sea kelp solution, bought it because my plants looked stressed. Does this add any nutrients besides micronutrients?

There is no way for us to know the answer to that question. There are many different manufactured brands of "sea kelp solution" and each is a different formula. But all the nutrients provided and the amounts of each should be listed on the container you purchased.

Dave

    Bookmark   May 4, 2010 at 4:25PM
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roper2008 (7b)

Thanks EG. We have acid soil here so I always add Espoma Lime in
the beds. I will add a little at fruitset.

Linda

    Bookmark   May 4, 2010 at 5:34PM
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ruet

EG, I don't know where you get the idea that no one appreciates your posts and insight.

If it wasn't for fine folks like yourself and gw's prominent posters, my ignorance-fueled brown thumb would have continued it's murderous rampage last year instead of producing a fair amount of tomato-topped snacks.

As Google seems to place gardenweb pretty high in it's index, I daresay you folks are adding appreciably to the sum of human gardening knowledge with every post. And Lord knows there's plenty of fud out there in need of dispelling. Someone somewhere is doing a search for Epsom salts to discover to their surprise that maybe they don't cure every tomato ill known to man.

Please keep it up.

Oh and how small of a SWC wick are you trying this year if you still have SWCs?

    Bookmark   May 4, 2010 at 5:41PM
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engineeredgarden(7, nw Alabama)

Linda - you're welcome. The Nitrate of soda is highly soluble, and it is 3 times as effective as agricultural lime for raising ph - so use it wisely.

ruet - I appreciate your thoughts. I used to post all kinds of threads outside of the square foot forum, but don't anymore. Everything is reserved to my blog now, as I don't have to defend myself on there from people that idolize certain GW members and their methods. I simply post about my ideas and experiences in my gardening environment, and don't force-feed anyone to try them for themselves. I'll continue to contribute occasionally, but will respectfully refrain from posting to a few member's threads.

I'm not sure what wick you're referring to on my swp's/swc's, but have all kinds of info about my setup at the link below.

EG

Here is a link that might be useful: My little place on the web

    Bookmark   May 4, 2010 at 10:17PM
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suburbangreen(8)

I have been working on a fertilizing schedule since I started growing three years ago. It takes time and experimentation to get it right. First of all, take into account the local soil type and it's deficiencies and surpluses or get a soil test.

All the college ag websites I have visited recommend a high nitrogen side dressing after fruit set and that makes sense to me. I like to give mine a shot of nitrogen after first fruit set, but since I grow organically it comes in the form of liquid fish or some type of tea. Since the nutrients in the organic fertilizers are generally less in NPK and are released slowly, I use more of a steady approach. This year I started in early Febuary mixing in compost, alfalfa based organic food pellets(4-1-1), bone meal, green sand and lava sand. I used liquid seaweed, liquid fish, and a tea made from the organic pellets, to get the plants going. I side-dressed with the pellets just before laying down a heavy layer of mulch when the plants started blooming heavily. Again, this fertilizer is slow-release(4-1-1), so they won't go into immediate high-growth mode like they would with a high-nitrogen chemical fertilizer. By the way, my plants are doing better than ever, with a pretty high rate of fruit set.

Good luck,

Pete

    Bookmark   May 5, 2010 at 12:29AM
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oley2010

I'm a second year tomato novice, planting with earl's hole method and using a fertigation setup. Would appreciate any advice on the best liquid or water soluable fertilizer to add to my plants after fruit set. Frequency? NPK concentrations? I have a 12 gal. tank watering 6 plants. Last year I added regular Miracle Gro, but after reading all these posts I'm sure there's something better out there for my situation. Thanks in advance for any help.

    Bookmark   May 5, 2010 at 10:50AM
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spaghetina(SF Bay Area)

I don't have any kind of knowledge to contribute, but I just wanted to say that EG has been inspirational to me. EG, I watched all your videos last year, and was so impressed with everything you built and grew that I ended up building 4 more raised beds for myself. I basically sat here and drooled over your entire setup, and everything looked wonderful, so I can't imagine that anyone would have anything negative to say about you. I appreciate all that you've contributed, so it sucks that you've felt the need to curb your posting because of a couple jackasses (whoever they are - I took a break from reading over the winter, so I don't know what drama has taken place).

    Bookmark   May 5, 2010 at 11:35AM
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sprtsguy76(Santa Clara Ca. 9b)

Love this thread. Bump!

    Bookmark   May 24, 2010 at 10:44PM
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mickyfinn6777(UK)

I have been reading all of the info here with interest.

However-I must add that the info generally is exactly the opposite of what is advised by well know gardening experts and tomato guru's over here in the UK and most of Europe.
The advice here-is for best results and fruit production and also compact plants with short internodes rather than tall straggly plants, it is best not to give any fertilizer to the plants other than what is in the starter mix when you sow the seeds-the plants are then left in that mix-even if potted on, until after the first flowers have opened and the fruit begin to set and/or all the fruit on the first truss has set etc, and then you begin the feeding program starting only at that stage, which usually amounts to liquid feed of something like Miracle grow with added seaweed mix, every ten days throughout the rest of the season until around mid July when you then change to a higher potash mix to harden the stem and ripen the fruit . apparently you get massive bumper crops if you do it this way.

Years ago I used to visit a tomato grower semi- pro with huge greenhouses full of them, all grown in raised beds of compost inside brick troughs thirty or forty foot long in double rows either side of his greenhouses, the compost usually consisted of a peat sand and loam mix with added fine grit, once the initial planting had taken place and the plants were established he told me that they got nothing else all season long except a side dressing of fish,blood and bone meal every couple of weeks plus water, and that is all,-every year his tomato plants were hung in reams of of tomatoes all the way down the plants and he always had queues of people every saturday morning queueing up outside his store shop front to buy the tomatoes as most of them said they were sweet and very nice flavour and they were the best for miles around.

So there you have it-two different methods and opinions.

    Bookmark   May 25, 2010 at 1:24AM
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