Am I understanding EC correctly?

[johnnyappleseed]

I fertilized on 5/5 using FF week 5 nutes. The EC of the solution was 1.2

On 5/8 I watered and checked the runoff and the EC was .7

This tells me the plant is hungry. But I made a mistake and forgot that I fertilized on 5/3. And by the looks of the deep green coloring on the plant and these brown spots on the leaves, I'm thinking that it's an excess nute situation. But how could that be with an EC of .7 (from being 1.2 a few days ago)?


It's purple caper cherry tonic.

 

[Sativa1970]

I fertilized on 5/5 using FF week 5 nutes. The EC of the solution was 1.2

On 5/8 I watered and checked the runoff and the EC was .7

This tells me the plant is hungry. But I made a mistake and forgot that I fertilized on 5/3. And by the looks of the deep green coloring on the plant and these brown spots on the leaves, I'm thinking that it's an excess nute situation. But how could that be with an EC of .7 (from being 1.2 a few days ago)?

Really need more basic information. What media are you using? What method, organic soil, drain to waste hydro...? What stage is the plant, ie. mid veg, early flower...? Did you fert 1.2ec on 5/3, and 5/5 with water run off .7ec on 5/7? How much run off are you giving her?

 

[johnnyappleseed]

It was really just an academic curiosity as to the drop in ec. I'm growing in soil/peat/perlite. Plant's in early flower.

I guess, maybe I should have rephrased, I'm assuming a drop in ec from 1.2 to .7 in 3 days means the plant is hungry. But the plant looks healthy.

Do you read the plant and let her ride and keep fertilizing once a week? Or do you feed with nutes during next watering?

 

[Roy Growin]

It was really just an academic curiosity as to the drop in ec. I'm growing in soil/peat/perlite. Plant's in early flower.

I guess, maybe I should have rephrased, I'm assuming a drop in ec from 1.2 to .7 in 3 days means the plant is hungry. But the plant looks healthy.

Do you read the plant and let her ride and keep fertilizing once a week? Or do you feed with nutes during next watering?

The drop in EC does not mean she is hungry, it means she is taking as much as she possibly can - perhaps too much

 

[Sativa1970]

Just curious is perfectly acceptable. Your plant didn't read or write the feed chart so trust the plant. The charts are a general average ballpark guide. With hundreds of strains and thousands of hybrids appetite can vary. The EC meters are just a communication tool to help talk plant.

The best way to explain it is like plates of food being set in front of the plant. Feeding is a new plate with all of the food groups set in front of them. Run off is collecting the old plate. If the plate had a reasonable amount of food to start, then an empty plate being cleared for the next meal is good. You can increase the servings but you don't want a lot left on the plate when you clear. Under feeding is always better than over feeding.

Not having enough run off is like not clearing the old plate. The last few pieces of food are added to the new plate. That plate will now have twice as many leftovers and so on. Minor overfeeding can add up quickly. That's why you do the PH water only cycle. Water clears the table and resets the PH. Take whatever volume of water you add before getting run off. Then add another 25%.

That help at all?

 

[Sativa1970]

Do you read the plant and let her ride and keep fertilizing once a week? Or do you feed with nutes during next watering?

Just re read this and wanted to clarify. feed on day 1, water on day 3 and feed on day 5, wait for the new week. If your run off EC is higher than feed water reduce the EC, not the number of meals a week. Many of the minerals can not be stored so it needs a constant supply.

 

[johnnyappleseed]

Not having enough run off is like not clearing the old plate. The last few pieces of food are added to the new plate. That plate will now have twice as many leftovers and so on. Minor overfeeding can add up quickly. That's why you do the PH water only cycle. Water clears the table and resets the PH. Take whatever volume of water you add before getting run off. Then add another 25%.

That help at all?

Yes, thank you. I put strings through the bottom of the (plastic) bucket holes that dangle into the drip tray. I have a 2" riser under the plant. (I got inspired by the ac infinity self watering base).

I usually water 32 ounces whenever the plant feels light. I pick up the pot. This pot is 6.7 gallons so I'll do 64 ounces if she gets really dry.

Just re read this and wanted to clarify. feed on day 1, water on day 3 and feed on day 5, wait for the new week. If your run off EC is higher than feed water reduce the EC, not the number of meals a week. Many of the minerals can not be stored so it needs a constant supply.

My schedule is usually: I wait until the plant feels light to water. I feed once a week. I'll give phd water in between only if the pot feels light. This is usually only once per week. So, feed on sunday, maybe water on thursday.

I can't imaging feeding/watering every other day....

Btw, im in a cold unfinished basement. Zone 7ab. Temps around 67-73.

 

[Sativa1970]

Ok, every third should be water. Feed Sunday, feed Thursday, water Sunday, feed Thursday and so on. That isn't a lot of water for 6.7 gallons, even if cool. Media drainage and plant roots will change the volume of liquid but the percentages are what you are looking at. At least 20% of the feed water you pour in the top should run out the bottom. Closer to 50% of strait water poured in should run out the bottom.

End of the run off EC should be close to the EC you just poured in. You only really need strait water if your run off EC is higher than the EC poured in top. Indicates a build up of leftovers on the table that need to be washed away.

 

[johnnyappleseed]

Ok I'll give it a shot. Thanks.

I assume I'm testing the runoff correctly, I just wait about 15 minutes after I'm done watering, there's probably a good inch of runoff in the saucer. I just swirl it around to mix it up and test that.

What do you guys do with all that runoff? I'm assuming not everyone has strings that wick it back into the soil.....

 

[Sativa1970]

First out can indicate media residual nutrient. End should indicate full replacement with new ec and catch tray will give an average of the 2. So first or end can be usefull but not really the catch pan average.

 

[Sativa1970]

Before work rudely interrupted me yesterday.
You are using a modified wick or "SIP" method? I thought you were running drain to waist. That explains why you only have to water maybe twice a week and so concerned with runoff EC. Running to SIP not waste is different.

Rinse the catch pan out before watering. It will get mineral build up from evaporation effecting pan EC. If your pan EC is higher than feed "water" dump it, rinse and water again to flush. Feed and pan should always be close to the same EC.

My runoff goes to other plants. feed house plants, garden, fruit trees or just spray it on the lawn. More useful than dumping it down the drain. Branches become tinder bundles for fire place. Trim gets turned into hash. Roots and veg go in composter for garden.

 

[johnnyappleseed]

Before work rudely interrupted me yesterday.
You are using a modified wick or "SIP" method? I thought you were running drain to waist. That explains why you only have to water maybe twice a week and so concerned with runoff EC. Running to SIP not waste is different.

Rinse the catch pan out before watering. It will get mineral build up from evaporation effecting pan EC. If your pan EC is higher than feed "water" dump it, rinse and water again to flush. Feed and pan should always be close to the same EC.

My runoff goes to other plants. feed house plants, garden, fruit trees or just spray it on the lawn. More useful than dumping it down the drain. Branches become tinder bundles for fire place. Trim gets turned into hash. Roots and veg go in composter for garden.

I should have been more descriptive in my initial post. I don't keep the reservoir full of water all of the time. When I feed or water I give the plants usually 64 oz. I feed from the top and it trickles through and fills up the reservoir usually a 1 to 2 in. I have strings resting in the drip trays that run to the interior bottom of my plastic pots. They usually soak up all the water in the drip tray with in 2 days and then I wait until the pots feel light before feeding/watering. I'm in an unfinished basement without a drain so carrying water buckets up the stairs outside gets old really quickly. I usually feed on Sundays and water once in the middle of the week. If anything, I'll water more frequently if they need it, but I have always just been fertilizing once per week. I use the Fox farm trio.

In the past 3 years that I've been growing, I've been trying out different things each time. I don't have much luck with organic (soil/pete). I think it just takes too much time to become effective and by then it's usually too late to course correct, hence the Fox farm trio. I don't do well with too many variables.

I have a dwc 5 gallon bucket that 'm trying out and so far, I really like the simplicity. I'm running sterile using Master blend tomato formula.

I've been watching a lot of Bruce bugby videos and a lot of what he says really resonates with me. I really like science -backed data.

 

[Sativa1970]

My grow rooms are all dwc for low maintenance, repeatability of growth. Aquaponics on pet tanks as water filter but don't care bought plants realy. Veg garden is primarily organic just to process plant waste. Bugby is a great source if you are into the science and experimentation.