fertilizer for containers

[UFXEFU]

I have two dwarft plants in 12 inch clay pots and need recommendations on applying fertilizer. I plan to use 15-30-15 blue stuff, calcium nitrate, and magnesium sulfate.
How much and how often should each of these be used?

Bob

[ginger2778]

What and how much did you put in with your potting mix?

[UFXEFU]

Originally Posted by ginger2778

What and how much did you put in with your potting mix?

I have mixed 15-30-15 blue stuff at 1 tsp to 1qt of water and water with that only three times. Basically very little fertilizer has been added so far. Plants have only been potted up six days.
Bob

[UFXEFU]

Looks like nobody knows or it's a "trade secret."

[Cole_Robbie]

When the plant starts to set fruit, I would swap your current blue stuff for 4-18-38. For in-ground plants, I have alternated the 4-18-38 and the calcium nitrate, then gave them magnesium when they began to show deficiencies.

As for amounts, I never was the type of person to measure anything. I think a good rule of thumb is to start at about half the strength that the manufacturer suggests, and play around from there.

If you re-pot the plants at all, it's a lot easier to just use Osmocote, then you don't have to fertigate as you water.

[MikeInCypress]

Can't go wrong with Texas Tomato Food once they have blossomed.

MikeInCypress

[Father'sDaughter]

I go with the Urban Farm Vegetable Fertilizer until they start to bloom, then switch to their Texas Tomato Food.

[ginger2778]

I like TTF too, but switched to a dry slower release food incorporated into my potting mix. My favorite it Espoma Tomato Tone, and I also supplement with Calcium nitrate, and Epsom salt. For me the amount of if Texas TF I had to use made it not so cost effective. At 1 tablespoon per gallon, that was 3 Tbs. per earthbox, and I have 47 earthboxes. You will need to figure out the appropriate amounts for your size container. Really you are just needing to supply your plants with any nitrogen, phosphorous, potassium, minor nutrients source since your potting mix doesn't have any. Keep in mind that tomatoes are heavy feeders, even dwarfs to some degree.

[PureHarvest]

Bob, I can't speak for the 15-30-15, but the calnitrate would be 4 ounces per 100 gallons and the mgso4 would be the same. When u get to the 2nd flower cluster, bump the cal nitrate to 8 ounces per 100 gallons.
I find it's easier to convert the dry ounces to grams and then divide by 100 to get the per gallon rate.
This gets fed to containers daily. In a 12" pot, not gonna need a whole lot until they get bigger.
4-18-38 pairs nicely with the other ferts. It is 8 ounces per 100 gallons in all stages and will supply the high levels of potassium that will be needed.
These powders are cheap compared to buying liquid concentrates if you will be feeding lots of plants over time.
You mix them into your bucket/tank one ingredient at a time.

[JaxRmrJmr]

Sometimes I fertilize twice a week at 1/2 gallon per plant and sometimes it is once a week with a gallon per plant. In either case, it totals one gallon of Masterblend per plant mixed according to the directions.

[Worth1]

A one gallon wine bottle makes a great measuring device and it is a lot of fun drinking the wine.
Worth

[txraddoc]

Originally Posted by Father'sDaughter

I go with the Urban Farm Vegetable Fertilizer until they start to bloom, then switch to their Texas Tomato Food.

This. I've used TTF for several years now and it grows monster dwarves.

[SharonRossy]

Ok I have a question here. I have two 10' x 3' x 18" boxes filled with Pro Mix to grow my tomatoes in. I have used a granular slow release fertilizer along with Epsom salts and lime. Is this the recommended method. These are not SWC and the bottom of the boxes are open to the soil below.
Then once flowering begins, I start with a diluted liquid fertilizer every week. My question is how much granular fertilizer should I be adding and should lime be added vs gypsum? The other question is about the fish/kelp fertilzer which I believe is added as a foliar application? Should it be used in con★★★★★★★★ with my set up? Thanks, Sharon

[AKmark]

4-18-38 is formulated just for tomatoes. It has been used by thousands of commercial growers, and besides observation, results are tested in a lab. It is one of the best formulas on the market for container tomato growing.

[PureHarvest]

Originally Posted by SharonRossy

Ok I have a question here. I have two 10' x 3' x 18" boxes filled with Pro Mix to grow my tomatoes in. I have used a granular slow release fertilizer along with Epsom salts and lime. Is this the recommended method. These are not SWC and the bottom of the boxes are open to the soil below.
Then once flowering begins, I start with a diluted liquid fertilizer every week. My question is how much granular fertilizer should I be adding and should lime be added vs gypsum? The other question is about the fish/kelp fertilzer which I believe is added as a foliar application? Should it be used in con★★★★★★★★ with my set up? Thanks, Sharon

Sharon, what is the analysis of the granular? What is it made from?

Both limestone and gypsum will supply calcium. Gypsum also supplies sulphur. Limestone also supplies magnesium (dolomitic supplies more than calcitic).
So promix comes with limesone already mixed in to buffer the acidic peatmoss, but it does not last all season.
How much lime and epsom did you apply per plant?
Id use whichever is the finest particle between the gypsum and limestone because finer particels will become available quicker. Either will supply calcium, and your epsom will cover your magnesium and sulfur. Your granular will give your NPK.
What is the liquid you switch to at flowering?
It gets complicated when you have lots of different ingredients.
You could just use your granular, calcium nitrate, and epsom and call it a day as it will supply everything you need.