Saturday, July 7, 2012

Blossom End Rot

This is a post I never expected to write. For the first time ever, I am battling the dreaded blossom end rot. It is decimating my black krims, attacking about half of the tomatoes on my heirloom plants, and has even moved to take a couple of my prized bell peppers in their infancy.

A bounty of rotted goodness
In past years, I’ve done just about everything the “wrong way” in terms of container gardening. I’ve used pots that were way too small for what I was growing. For example, last year I put four Abe Lincoln tomato plants into each cat litter bucket, which holds about 5 gallons of dirt. I’ve used the cheapest dirt I could find anywhere. The stuff I used last year was so heavy that it pulled away from the sides of the container as soon as it dried out (which was every single day). I might as well have just used dirt from the yard. I would leave for 3 days at a time and when I would get back everything would be so wilted I would wonder if it would come back or not once it was watered.

All of that, and I never dealt with blossom end rot.

This year, I bought nice big containers, much better soil, I’ve been watering far more consistently, and the plants have far more room to grow than ever before. Yet now, nearly every singly black krim tomato I have has blossom end rot. On the other heirlooms it is about 50%. I had 4 green zebras with it also, but that plant’s fruit seems less bothered than the others. All the cherry varieties are fine, with no blossom end rot in sight.
The cherries are doing great!
I’m at a bit of a loss. Reading up on it merely clouds the issue. Blossom end rot is caused by calcium deficiency in the plant itself, but not necessarily the soil. Often the issue is that the plant cannot draw the calcium from the soil, which can happen for a number of reasons. It could be too little water, too much water, too hot, too cold, too windy, not windy enough, or it just might have a headache. Okay, I made those last two up, but essentially the cause could be anything, which makes it tough to pin down.

I don’t think it is too much water, as it has been hot and very dry here. I think it has rained once in the past two weeks for more than 2 minutes. I’ve been watering about every other day or so, and in the past I’ve never had an issue giving a potted tomato that was 4 feet tall “too much” water, especially since the containers have ample drainage. As far as too little water, that is possible, but as I said before my plants would be wilted on a daily basis in the past because they were in ridiculously small containers. I had one poor Abe Lincoln tomato in a gallon pot, and it would wilt every day. Still, I got a few nice fruits from that plant, and I did not get any blossom end rot. The tomatoes this year have very rarely wilted, but the dirt is pretty dry when I water them (as tested with a soil moisture tester).

Most of the peppers are doing great as well
This leads me to the temperature issue. It has certainly not been too cold, so I can immediately toss that one out. It’s possible that the issue could be the heat, especially since it has also been quite windy for the past couple of weeks. The temperature has been in the mid 80’s to low 90’s for a while here, and on the porch it can be a good 10 -15 degrees warmer than that when the hot afternoon sun is blazing down on the plants. Couple that with the almost constant wind lately, and it can be like a giant convection oven out there. I have read that heat and windy conditions can stress the plants, leading to less calcium absorption and blossom end rot, so it seems possible. 

One last possibility could be too much nitrogen rich fertilizer, but I also don’t think this is the case. I used some organic chicken feather meal based fertilizer back in early May, and I applied one dose of Miracle Grow tomato food in June. The chicken meal stuff (I don’t remember the exact name) was low in nitrogen and high in calcium, and the MG tomato food was pretty even across the board. I also use fertilizer sparingly, and apply less than the dosage called for. I suppose it is possible that the added fertilizer, along with the Sta Green mix, has a bit too much nitrogen and is interfering with calcium absorption. This seems unlikely, given that I mixed the MG weak and added maybe a cup of the mix to an 11.5 gallon container once this summer.

From the top, the blossom end rot isn't noticeable
Not knowing exactly what is causing the blossom end rot makes solving the issue a bit difficult. I have considered buying a foliage calcium spray, which helps the plant absorb calcium quickly. It won’t cure the currently afflicted fruit, but hopefully it will help new fruit. Then again, this stuff has its supporters and detractors, and I tend to like to avoid adding stuff from a bottle when I can (a lesson I learned from aquarium keeping). It can’t really hurt, although many say that it does little to help, and the plants will naturally recover and begin producing healthier fruit, making the spray seem effective when the tomatoes would have been fine without it. I might try a test and spray it just on my black krim plants, since I am most excited for them, they are almost all being ruined by blossom end rot, and at this point if I get a few plump, rot free, ripe black krims I am not going to worry about whether it was the spray or just nature taking its course.

Carnival pepper mix (I think it is a white bell)
Luckily,  the peppers mostly seem fine, aside from a couple that I lost to blossom end rot. I normally lose one or two anyway, so that is no big deal. Hopefully it stays that way. As I said above, all of the cherries are fine. Almost all of the green zebras are also doing well, and seem rot free. It’s the heirlooms for the most part, and especially the black krims, that are being affected. Some of the heirloom plants were the seed mix, so it is possible that some of them are actually also black krims, and I just don’t know it yet.

In my limited (and hopefully soon ending) experience with this issue, there is almost nothing more frustrating than blossom end rot. When you have healthy, green, large plants loaded with tomatoes, and almost every one is being destroyed by blossom end rot it can be very discouraging.

The okra is loving this sun and heat!
On a positive note, the eggplant and the okra seem to absolutely love the blazing heat and hot wind. When we got home from a camping trip yesterday, almost everything looked wilted except the okra and eggplants. I think the okra grew 4 inches in a few days. We have even harvested two pods from the red okra plants, which are only about 8 inches tall. In fact, they didn’t even begin to look healthy until it became unbearably hot out here, and now they look beautiful! If nothing else, we know that okra and eggplants seem to love the heat and wind on the porch. Hopefully in a few weeks I’ll be writing a post about how all of this blossom end rot stuff has resolved itself and the tomato harvest is rolling in.

White eggplant emerging
 Until next time, happy gardening!


  1. Blossom end rot is no fun, I had a few years ago and it took a season to fully recover. We just put a bunch of egg shells in the soil.

  2. I'm with wendy I also had the same thing added eggs shells and perfection

  3. Thanks for the suggestions! I decided to go with calcium spray for an immediate kick, and in the future I am going to save eggshells and mix them right into the potting mix before planting.