Indoor Hydroponic Strawberry Issues

erikas · May 25, 2022, 2:03am

First, apologies for a very random question, but this has been dogging me for over a year now and I don’t know where to turn other than the mass of expertise on these forums. Almost all of my (gardening) time now is spent focused on my outdoor endeavors informed by the many brilliant posts here (which I’ve lost many, many weekends reading in detail) and one day I’m sure I’ll have some good information to share. But, for now…

I’ve been trying to grow hydroponic strawberries indoors year-round in an Aerogarden for about 18 months now. I buy bare root day neutral (occasionally everbearing strawberries), I place them in the Aerogarden, and they absolutely thrive leafing out quickly, flowering, and growing delicious strawberries. (Day neutral as there won’t be chill hours in my indoor grow room.)

I read on the Internet: a) to disable the Aerogarden drip watering system pretty much completely (5 minutes on, 3,000 minutes off) to avoid root rot; b) to use Fox Farms nutrients instead of the standard Aerogarden nutrients (I currently use Grow Big); c) to aerate the water with an aquarium aerator. Bare roots are placed in the plastic wire baskets directly.

For the first six months, I had no issues with the plants (other than lots and lots of runners I had to continually cut off) and had many delicious strawberries. My project was a success against all odds. I even transplanted some of the runners outside by using soil pots to spawn new plants. Life was good.

But then the plants all died out. I bought replacements. They would all thrive, leaf out quickly, start to create strawberries and then… die. I would replace them again and this cycle has continued for most of the past year. All of my initial success has withered on the vine.

I discovered via a post here that the place I’ve been buying bare root strawberries for over the last year (but not the initial six months where I had success) is known for selling diseased plants. I’m coming to believe that maybe my grow room has some sort of disease from those. We removed all of the old strawberries about two months ago, cleaned the entire strawberry grow area thoroughly (sanitizing where possible), and replaced with new strawberries from sellers with a strong reputation.

But now it’s happening again, one plant at a time.

What is going on with these strawberries? Is it disease? Am I missing nutrients? Too much water / too little water? Too much / too little aeration? Or something completely different? I’ve tried to search articles on strawberry diseases, books on strawberry diseases, and the forums for anything like this, but nothing seems to match (even though it’s obviously tough to tell so I may be missing something really obvious).

Also note that I mostly grow hot peppers in Aerogarden in my grow room and they’re all doing just fine, but, when we cleaned everything up about two months ago, we didn’t remove/replace them so they could be a vector for disease. We have some likely fungus gnats floating around in there, but nothing excessive. I had two serviceberry and six thimbleberry plants in pots in there for the past few months waiting for Zone 4 weather to warm up for planting and they could’ve also been vectors.

Here are some photos of the issues:

Close up:

And then another strawberry plant that’s just starting to see issues (an Albion):

And finally a neighbor plant that is still unaffected (a Delizz):

Any ideas from the brain trust here?

Adamsmasherz · May 25, 2022, 5:35am

Hello Erikas,
At this point I have a fair bit of experience (and unfortunately plenty of problematic experiences) growing hydroponic strawberries. Out of any fruit/vegetable that I’ve grown so far, strawberries are some of the trickiest to grow hydroponically. But its certainly possible!

A couple of questions for you:

How big is the aquarium air pump you are using?
How do the roots on your plants look when you start noticing foliage issues?
Do you ever completely empty the tank, sterilize it and then refill it with fresh water/nutrients?
You mentioned you sanitized, but what method did you use?
What is the pH and ppm (or EC) of your nutrient solution?

erikas · May 25, 2022, 12:38pm

Some quick answers (and I’ll try to follow up with more details, but, as I’ve found I’m quite allergic to pollen from the pepper bushes, I now try to stay out of that room unless I’m about to hop in the shower):

How big is the aquarium air pump you are using?

I’m not quite sure how to answer that question. I’ll check later to see if there’s any metric on the unit itself, but it’s pretty small. It’s certainly enough, though, that the water is relatively frothy when I look at it. There’s lots of oxygen getting in there… not sure if it’s too much.

How do the roots on your plants look when you start noticing foliage issues?
I haven’t noticed anything unusual, but I’m hardly an expert and I wasn’t consciously checking for issues. I’ll try to check for differences between the three berries I have in there right now, though, to see if anything more subtle is going on.
Do you ever completely empty the tank, sterilize it and then refill it with fresh water/nutrients?
I empty and refill every 4-6 weeks now. I do not sterilize it when I have it in production. I’m just worried about the time it would take to really clean it while the strawberries are out of the water. (I obviously have between the last attempt and this attempt, however.)
You mentioned you sanitized, but what method did you use?
Dishwasher with high heat. I’ve read that vinegar would work, but I’ve been assuming (perhaps incorrectly) that the dishwasher would be my most thorough option. (Detergent could obviously be an issue, but my problems started long before everything went into the dishwasher.)
What is the pH and ppm (or EC) of your nutrient solution?
I haven’t measured pH of the nutrient solution… not sure if there’s a standard for the Fox Farms Grow Big. I could probably check, but I don’t really trust any of my pH meters as I get wildly different readings then when I sent things off to a lab. I’m adding one dose of nutrients every week with the dosage set by the syringe I bought a while back (which was, in turn, calibrated to something I read on the Internet as the best dosing size and interval for strawberries in Aerogardens using Fox Farms Grow Big). I can try to research what that size is.

House water that I put in there is around a pH of 6.0-6.5 for what that’s worth. Unless there’s a big difference between hydroponic and soil, I think that at least should be good for the strawberries. But no idea on the impact from the nutrients.

I’ll try to get more data over the next day or so in any case.

Thanks for your help here. And, yes, I know strawberries are supposed to be incredibly challenging in these environments. I just got teased by my great success in the first six months and want to get back there. Maybe it’s a lost cause.

swincher · May 25, 2022, 3:52pm

You should definitely get a ppm/ec meter if you don’t have one. Years ago when I grew a …err… “flower” garden hydroponically, I quickly learned that most problems stemmed from either too concentrated or too diluted reservoir nutrients. You can’t just follow the packaging guidance, you need to target a particular ppm.

Also instead of a pH meter, just get a testing solution where you put a couple drops in a vial and check the color. That will be more reliable. Make sure you check the color in sunlight, not under the grow lights though! Then you should have pH up and pH down solutions to adjust pH when it’s out of range. This is very important for hydroponics.

As long as you have sufficient aeration (sounds like you do) and your ppm and pH are within range, you should be good to go.

One last thing: I always found that roots were happiest if the grow baskets in DWC hydroponics were filled with clay pebbles, like these, rather than just loose in the basket:

But I’m not sure if strawberries are different in that regard, and most of the root mass ends up hanging out of the basket either way. Also those baskets look too small for clay pebbles anyhow.