I am growing tomatoes in 5 gal SWB and using a 20-20-20- fert. and have large plants loaded with glooms and toms. it looks real good. I have used it before with success so I have great hopes this year. Ill keep you posted on my luck.

I use liquid, soluble ferts in WC reservoirs.

I use DynaGro Foliage Pro 9-3-6 which contains all plant nutrients including calcium which most do not have.

For tomatos and many veggies where I want the K as high or a little higher than the N I also use DynaGro Pro-Tekt 0-0-3. By adding both to the reservoir the 9-3-6 of the Foliage Pro effectively becomes 9-3-9. Adding twice the amount of PT would make it 9-3-12. With these 2 products I have no need of any other fertilizer for containers.

These products are not found in garden centers, but in hydroponic stores or online.

So, that answers the question of what I use, but how have you concluded you are experiencing a K deficiency? What is your weather like? I suspect it's on the cool side still which can result in nutrient problems that will clear with improving weather.

Get some "Tomato-Tone" - especially if you suspect nutrient washout which is common in containers. It has all the micro-nutrients and trace minerals your plants need. You can also add a generic 10-10-10 or (like above)a 20-20-20 slow release fertilizer, but don't overfertilize. Buckets can cause an initial concentration of fertilizer that can shock the plants.

Ted

Justaguy2

By looking at the foliage on the plants and comparing it to pics and descriptions on the net. It's only 2 of my biggest fastest growing plants that are showing this so far, the rest are still deep lucious green. And no, it has actually been unseasonably warm here in the great white north.

Containerted

No there's no washout as the SWB's are a closed system, i wish i could get my hands on some TT, alas Espoma has no retailers for their products in Ontario (this may be an idea for a new business for me ;) ). I was simply wondering if i could have already caused nutrient lockout by adding that second fert with HIGH P (90% of wich will probably never get used by the plant). My plants have been in the buckets since mid april and all were doing great, 9 of 11 still look fine.
Thank you both for your replies.
I guess it's time to search out some hydroponics stores.

PS Has anyone tried out MYKE(i forget fow to do the trademark sign) tomato fert. It looks similar to TT but i don't wanna go that route if i don't have a testimonial of someone who has tried it.

I know SWB's usually don't have nutrient washout, but I've seen many folks fill the water reservoir until they get runout and then keep the water going to wash out any debris.

If you suspect K deficiency, how do you think you arrived at that point this early in the season? Even straight potting mix with no additional fertilizer will not give you mineral deficiency problems this early. If you did a standard SWB setup at the beginning with fresh mix and all, how can you have ANY deficiency at this point?

It sounds like you may have achieved a serious Fertilizer Imbalance.

Good luck with your pursuit of the problem.

Ted

Ted,
the plants have been in the containers for a good 1.5 months. Whether it's a deficiecy or imbalance i don't have a clue but it does look like the plants are not taking up enough K. The potting mix i used is pro-mix bx so it is devoid of any nutrients. The only thing thaty does come to mind is lockout due to all that P present in the containers from using a fert containig too much of it.

Excess P generally results in micro nutrient deficiencies. I have never heard of it being able to limit uptake of potassium.

Justaguy2
I don't know what to tell ya. What i have and what i see in the plant pathology files, i forget the addy now, fits like a glove. Both pictures and description matches exactly.
Now i could be wrong and i didn't anticipate to run into this problem this early in the season but that's just one more thing for me to learn.
Do you think it could be from not having enough lime? I didn't add any to the BX as i was afraid of raising the ph too high.

I did try to resolve the problem by flushing the containers putting down a fertilizer band (can't get my hands on any hydroponics ferts fast enough)and hoping for the best. Will update if anything changes for better or worse.

Lack of lime wouldn't cause a K deficiency either. Most commercial mixes that are bark or peat based come pre limed anyway.

About the only imbalance that would be at all likely to induce a K deficiency would be too much magnesium. Overdoing Epsom salts might accomplish this.

So, if you wish to analyze this further please let us know the following:

1. What is the potting mix and more importantly is it wet an inch down or just moist?

2. What fertilizer(s) have you been using. How often and what strength?

3. What have the average day/night temps been the past 3 weeks?

4. How large are the plants and do they appear to be growing?

1. Pro-Mix BX it is slightly moist an inch down, pretty dry only on the surface, and when i dug into it a bit last night to put the fert strip down there were tons of fine roots in there.
2. I've been mixing about 2.5 ml of MG 24-8-16 and 2.5 ml of Vigoro (i think it's 15-30-15) per 5gal or (25l) of water and watering with that daily. It works out to less then 1/14th of recomended strength for a bi-weekly application.
3. Day temps until the last couple of days have been in the mid 20's but that's Celsius (i guess that's high 70's low 80's F???) Nights have been at least 10-15 C. Until mid may the plants were protected under a cloche/low tunnel.
4.The plants most affected are about 2.5 ft tall with many stems and suckers, lots of flower and a few fruit formed too.Both are determinate (Manitoba and Sub-arctic Maxi).They all appear to be growing, i got one more plant (this one is an ind. Calli Orange) now that's starting to show similar symptoms on it's oldest leaves.

Is it possible that a disease could present itself with similar symptoms to K defficiency?

Here is what I would do if you are pretty confident this is a nutrient deficiency:

1. Flush the soil by running several gallons of water through it.

2. Flush the water reservoir.

3. Add nutrients to reservoir at 100% of normal (label) strength. (trust me, you won't harm your plants)

4. Wait a week to see if things improve. Note: Damaged leaves may not and probably won't recover. Instead you should see the progression from oldest to newest leaves stop.

When it comes to deficiencies there are acute and chronic types. Most of the time we talk about acute deficiencies which is when a nutrient just isn't available for whatever reason. Chronic deficiencies occur when the nutrient is available, but not in a high enough amount to meet the needs of the growing plant.

When dialing in to the proper dilution rate in SWC, chronic deficiency is more likely than acute. It simply means that at no point in time is the strength in the reservoir adequate for the plant's needs.

For comparison purposes, I use 1 ml per half gallon of Foliage Pro 9-3-6 (recommended rate is 1 tsp/gallon so approx 1/5th dilution) for watering seedlings growing under lights indoors.

When actually growing outside in SWC I keep the reservoir between 1/4th-3/4th strength at all times, depending on the growth rate of the plant. Right now with cool weather and small plants it's 1/4th strength, in summer with producing toms it's 1/2-3/4th strength at all times.

Your problem *may* simply be that the amount of nutrients available on a daily basis is lower than the plants require. Given your 1 ml per gallon dilution I would suspect that the plants have simply reached a stage where it's no longer adequate.

Thanks Justaguy, you may well be right, i will try that on the plants that i hadn't added the fert strip yet. I will eventually get it right. On a side note i got 36 plants in a raised bed that are looking glorious, that's why i'm leaning towards nutrients, rather than environmenal or disease/pest problems.

Jag - thanks for your input on this subject! Like you said, to get the proper NPK ratios best suited for tomatoes, you just about have to mix your own. What I can't figure out, is why nobody will market the correct mixture. I've found some water soluble ferts online that will work very well, but it has to be purchased in bulk......

EG