Pepper flowers dropping

[Jonathan Kadish NYC AA Chair]

I have a very healthy pepper plant with many flowers but the early ones are dropping. My system is indoors but I understand that peppers should be self pollinating. I have read that an excess of nitrogen can prevent fruiting. Indeed my nitrates are in the 60-80 range which I would guess is high. I am doing some water changes to get it down but I am wondering what is the ideal range? Any other changes I should consider making.

PH 7

Temp 75

[Vlad Jovanovic]

Hi Johnathan, I can't really say why your particular flowers are dropping since many things seem to cause that phenomenon, but while growing indoors too much nitrogen, or too little light (or both) might be a good place to start. Are they Bell type peppers or some sort of spicy peppers? Are the flower petals dropping off above the sepal (the green star shaped thing), or below it?... Or is it at where the base of the peduncle (flowers stem) meets the branch. I'm betting that the base of the peduncle is flattening a bit, drying out then the whole flower (peduncle and all) is falling off...?

Are you pruning the axial flowering suckers, or just letting it go wild? (letting things get too unruly sometimes results in flower drop...probably due to insufficient energy transfer...which is P related)...

I doubt your place gets very cold (below 62-63F) at night, so that's probably not it? 

[Jonathan Kadish NYC AA Chair]

Thanks Vlad,

Yeah they are drying up at the base and the whole flower is droping with the stem attached. It is a hot pepper with what are supposed to be small fruit. I haven't pruned but if you think that would help I'll snip away. I'm on about 12.5 hours a day HPS.
It is growing with basil ... hope they are compatible.

[Vlad Jovanovic]

Nitrogen is probably a bit high, but also I'm seeing in the photo that the peduncles are quite purple. It's ok to get a little purple streaking here and there on stems and some branches, but really that is a sign that the plant is P deficient. Check the undersides of the older leaves...

Biochemically, P plays a key role in the plant’s energy transfer system “highenergy” bond compounds i.e...adenosine triphosphate (ATP), adenosine diphosphate (ADP), and phosphocreatine, which release energy for plant metabolic activity, and things like flowering and reproduction take a lot of energy...When there is not enough P certain sugars will build up causing the formation of the purple pigment (anthocyanin) that you see. Notice the rather extreme purple discoloration of the peduncle. I should add that P uptake is somewhat temperature dependent, meaning coldish temps will interfere with uptake even if there is enough P in solution. 

I'd suggest keeping the light on for 14 hours, drop or otherwise use up some of that N, and maybe foliar feed some rock of phosphate or an otherwise immediately bio-available P source (so no bonemeal and whatnot)...

I wouldn't freak out though, a few dropped flowers is not a big deal...unless it gets ridiculous and too many drop. A good hydro store should have some P-K nutrient you could spray foliar, since you probably don't want to make your own at this point...

[Steve Champion]

I always thought that peppers needed heat to reproduce.... I suppose I could be completely wrong tho!!

[John Cubit]

Jon,

I grow a wide variety of hot peppers and each require very different environments.  What species are you growing?  I know that I have a species of  Thai mini chilies (bird chilies) that require water temps and media temps over 75 as well as 6 hours of direct light and high nitrogen.  I have other peppers that do not like as much water as a normal grow bed so I have  to slow down fill rates.

I always recommend growing peppers with other plants as the peppers will often keep other insects away.  Also you may want to place a small battery operated fan that blows on the peppers to spread pollen, yes most are self pollinating but most require the pollen to break free, this can also be done be just lightly tapping each flower for a few days after they bloom.  You may also want to concider misting the plants when the lights are off, this can help with premature flower drop.

I will admit I am new to Aquaponics  but have been growing peppers in soil and alternative media for years.  Currently I am trying to give myself 12 months of growing season by growing from the best plants I have using cuttings in an Aquaponics system.

John

[John Cubit]

That can be an issue if these are seedlings.  I have plants producing fruit at 50 degrees.  It will always make a difference on the ripening of the fruit though.

Steve Champion said:

I always thought that peppers needed heat to reproduce.... I suppose I could be completely wrong tho!!

[David Freitag]

peppers also require a good amount of calcium to set fruit properly.

[Roger]

I've also noticed though experience, when my grow room got too hot, that heat will cause petal drop.  Same with tomatoes.  Although Vlad brings an interesting point to the table by saying it is a P deficiency.  Although I've also grown purple jalapenos and their flowers and the stem of the flowers are extremely purple.

[Jonathan Kadish NYC AA Chair]

Interestingly enough, when I came back from being shut out of my house with no power and no heat from the hurricane, this plant decided to put out some peppers. The the pump was dead, the grow light was dark and I manually pumped it 2 times in 5 days. The plant had only indirect light from a window several feet away. I didn't address the P so I wonder still what the plant was looking for, stress?

[Chris MIller]

Less water?

Jonathan Kadish NYC AA Chair said:

Interestingly enough, when I came back from being shut out of my house with no power and no heat from the hurricane, this plant decided to put out some peppers. The the pump was dead, the grow light was dark and I manually pumped it 2 times in 5 days. The plant had only indirect light from a window several feet away. I didn't address the P so I wonder still what the plant was looking for, stress?