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Ontario

So i have 2 questions, first of all, using Calcium Nitrate at about 0.7 EC for the whole fruit growth season, will i get an issue with too much nitrogen? I dont think so, but at 15.5% nitrogen, it could be a little much?

Secondly, I was thinking ratios: soil test results we look for 6-20:1 Ca:Mg, 10-15:1 Ca:K, 80-1000:1 Ca:B, 200:1 K:B, 2:1 Mg:K.
But I assume that the plant doesnt use nutrients at those ratios, so obviously i shouldn't do exactly those ratios, but what ratios of those major nutrients should I do all season?
I was thinking per 1000L tank Calcium nitrate: 500 g, Potassium sulfate: 350 g, Magnesium sulfate: 200 g, Borax: 5 g
This should only be like 1.2 EC total, so i could probably push Potassium or Calcium higher, or the whole solution higher, maybe up to 1.8 or 2.0 EC by day 25 or 30?

I dont know though, im still really new to this whole being particular with my fertilizer regimen.

7/5/2026 9:01:15 PM

Grittyville, WA

There is an optimal total EC of 2-3 ish? For most crops? Seems like watering in a solution at 2 EC might be on the rich side but I dont know. What about doing a tissue test before deciding on final feed ratios? I read that an 80:20 ammonium to nitrate ratio is good but I think the Patons only use nitrate and they are the top growers so there's plenty of room for debate.

7/6/2026 3:30:36 AM

Ontario, Canada.

Ammonium ties-up Ca. So as A -cations compete for exchangeability... Zero when the fruit is actively growing otherwise you may acquire a date with low weights and or splits.

Think stay the course or slightly boost to D20 with Ca/Nitrate and then reduce the ratio while lowering N inputs to focus on potassium.

[Last edit: 07/09/26 7:00:22 PM]

7/9/2026 6:57:41 PM

Grittyville, WA

Actually there could be a debate about that, while true that it is a cation, I'm not sure it has been shown to greatly affect calcium.
Nitrate is an anion yet it may be worse than ammonium because of less efficient use of water and energy. Both of which can negatively affect calcium as well. But perhaps I am wrong.

Cal nitrate is supposed to help with BER in tomatoes (and I think it does) but I dont think it will do very much for the fruit size. Ultimately calcium is an active transport molecule, as I understand it. So a portion of the uptake depends on the health of the plant's roots.

Just some alternative arguments but difficult to know the whole truth? Because all the science gets really real, really fast.

7/9/2026 10:14:04 PM

Ontario, Canada.

Perhaps this is better, doesn't tie up more like Ammonium out competes Ca. In plant nutrition, ammonium (NH4) and calcium (Ca²) have a well-documented antagonistic relationship. Because both are positively charged ions (cations), they compete with each other for absorption sites on plant roots and transport channels inside the plant. Widely this is well studied and demonstrated.

[Last edit: 07/10/26 8:25:19 AM]

7/10/2026 8:22:24 AM

Ontario, Canada.

One of the most important points to follow is to use acidic water. Fertilized Irrigation water in a lot of situations needs to be treated to Sub 6.0 pH for maximum availability of any Ca mix.

7/10/2026 8:30:43 AM

Grittyville, WA

The nutrient availability/ph diagrams show calcium being best at 7.0 or above. This might be wrong? These charts may be based on assumptions.

https://scienceinhydroponics.com/2021/02/nutrient-availability-and-ph-are-those-charts-really-accurate.html?print=print

It's such a coincidence you say that calcium is best 6.0 because I was just raising the ph of my water last night because I felt quite certain that I would increase the likelihood of BER at that Ph. Do you have an info source? Is it because certain myco likes a lower ph or are we talking hydroponics here? I'm a bit ignorant so you'll have to forgive me for not knowing this stuff.

7/10/2026 12:18:42 PM