Heat-resistant lettuce experiment

One of the frustrations about growing salad greens in the midwest is the fact that just as soon as the crop begins to reach maturity, the weather turns unreasonably hot and the plants bolt and turn bitter.
To solve this problem, I began researching varieties of lettuce that were claimed to be resistant to heat.

On May 1, I planted a 24 foot row with 4 different varieties of lettuce that claimed heat resistance. These are, top to bottom, Summertime [iceberg type] Adriana [butterhead] Nevada [Batavia] and Jericho [romaine]. I intend to see if they can really stand the summer heat without bolting.

Summertime is the only one of these I have grown previously, and I was very happy with it. At five weeks, the leaves are already starting to curve and make heads. I am not very happy with the germination of the Adriana. These were pelleted seeds. [I sowed a little Tom Thumb to fill in the gaps a couple of weeks ago.] The Nevada, on the other hand, was also pelleted, and it has proved the most vigorous of my four varieties. So far it gets high marks. The Jericho is less vigorous and the plants a bit smaller at this stage.

Today, June 7, the temperature reached 86 degrees - the fourth consecutive day of temps over 80. This is of course unseasonably hot for this time of year in zone 5, which makes it an excellent test for my lettuce. Although the plants were unhappy and wilted-looking in the midafternoon heat, the thinnings that I picked were delicious, crisp and sweet. So far, so good.

The same row from the other side of the garden

wow - great idea! Keep us updated!
bre

Yes, please keep us updated. I tried lettuce over the winter this year and all of it was bitter, we get into the 80's pretty often until December and high 70's a couple of times in Jan and Feb.

I'd love to know the results of your experiment too! We get way too hot for lettuce down here. I've tried it several times in the spring but it always gets bitter before it even finishes growing. And like pieohmy, I've tried it in the fall with the same results. For now, I've given up trying to grow it.

After last year, I can call Summertime a success. It stood until the end of July.

Thanks for posting this info! I have Summertime seed and was debating on whether or not to try it. You have a beautiful garden there!

I planted it again 2 weeks ago, which is probably pushing it for a head lettuce, and I put in some more Jericho, as well. If you don't push the limits, you don't learn what they are.


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Great idea-I live in zone 5a and I have the same problem. I'm trying a spinach mix from Pinetree seeds this year-some of the varieties are supposed to be more heat tolerant. So far so good-although we haven't really had any hot days. I had only one plant bolt but the rest of the spinach is wonderful-with no bitterness. I haven't had a lot of luck with my mesclun mix-VERY slow to germinate. Keep us posted on your "experiment". Deb

Spinach - total wipeout this year. I've tried different varieties, planted in different spots, it just won't grow for me. I think it might be the soggy ground, or I have some spinach-specific soil deficiency.

Radishes a wipeout, too, because of the wet soil.

How do you keep bunnies and other critters from eating your beautiful crops?

The damnrabbits don't seem to care for lettuce, I'm glad to say. They do like spinach, and I cover it with chicken wire. Also peas.

I thinned the lettuce again today, and the Summertime is coming right along, starting to head. So far, though, the winner is the Nevada Batavia. Beautiful little heads! The Jericho is falling behind the others, which may have something to do with its being at the worst-drained end of the row.

I'd post photos, except that my photo card reader is switching off my wireless connection.

The bunnies don't stand a chance-I have a "guard cat" named Moe. He has caught full grown rabbits and brought them home. No problems with other little critters either-

UPDATE: I didn't plant any leaf lettuces for the experiment, only heading varieties, but I can report that the red leaf lettuce New Red Fire is just excellent. I'll grow this one again next year.

[It's visible in the photo above, the dark red lettuce]

debee, my garden cat is Tim. He doesn't get the biggest rabbits, tho. His predecessor, the admirable Zack, feared no rabbit, no matter how big.

That is a beautiful garden. I am new to gardening, and couldn't quite figure out what I was supposed to be doing. I like your way.

Karen

I've found that Jericho stays sweeter longer than any other kinds. I'm going to try Summertime and see how that does.

Looking again at the photo, I want to mention that New Red Fire has turned a much darker color as it matures. The hearts are a beautiful glossy burgundy.

Where did you get your NRF seed?

Johnny's Selected Seed. I got the pelleted seed.

I notice that they have a page up now featuring heat tolerant lettuce. I wonder if I inspired them!

It's 101 degrees here at 11 p.m. We're bouncing between 112 and 115 during the day. I doubt any lettuce would take this heat but if you think one of those might, I'm game to try. Love lettuces and greens and can only grow them in from fall through early spring.

That kind of heat is beyond what we get here, so I can't say.

If this lettuce stands through July, with highs in the 90s, I'll consider the experiment successful.

For a more extreme test, I ought to plant now and see if it stands through August.

This page http://www.johnnyseeds.com/catalog/search.aspx?scommand=search&search=heat%2btolerant%2blettuce&source=e_0608_HTL_hg_cr_heat%2btolerant%2blettuce
from Johnny's Selected Seeds has some I didn't try. Adriana is said to be an "improved" Ermosa. I've heard good reports of the Anuenue but haven't tried it myself.

Hi LTilton, I've planted Anuenue & Jericho and had both of them stand into August, with no browning and no bitterness. It might be a little cooler in the summer here though as compared to you. Of the two my favorite was Anuenue for taste & texture. They are pretty amazing lettuces! Thanks for your post - I'll have to try that Nevada.

I think I'll try the Anuenue next year, hearing great reports of it.

I'm so happy that you have done this test for us and thank you to everyone else reporting on what has done well for them. I can't wait to try some of these lettuces this fall. I always thought I could never grow lettuce.

My goal is to have salads with lettuce, cucumbers, and tomatoes all from my own garden, all at the same time.

I don't think it will happen this year, tho, with the slow start the warm-weather crops got.

I have plenty cucumbers and tomatoes. We need to trade vegetables, LOL.

Last year we had lettuce all summer growing under shade cloth, harvesting small and planting every few weeks. We're have good luck with the Jericho in between the rows of tomatoes and Fedco Summer Lettuce Mix without shade cloth. I also have but haven't planted yet: Kagraner Sommer Bibb, Pablo Batavian, Summertime Iceberg and Anuenue (I need more space to experiment!). Now if we could only have tomatoes all winter!

I'm about to rip out a row of bolted leaf lettuce that was mislabeled so I don't know what it is. But it leaves room for another phase in the experiment.

Of course the trick at this time of year is to get it to germinate.

To improve germination, I use a 4-gallon hand waterer with a rosette and water everyday. I use rain water or let the tap water de-chlorinate overnight in a plastic trash can.

Here's the Fedco summer mix - we had it in a salad tonight with Cherokee Purple / White Brandywine tomatoes. Yum Yum.

I love baby greens!

Got a new photo card reader, this one seems to work.

Here's the experimental row as of 6/18/08

New Red Fire leaf lettuce.

That's it at the far end of the row to the right of the lettuce row.

Adriana butterhead. Not from the experimental row but an earlier planting. Still holding very well.

Summertime. This is a thinning from the experimental row.

Nevada. Two little heads that I thinned from the experimental row.

Any updates on taste, Ltilton? They sure look yummy!

They are all quite excellent, not a bit of bitter.

The only lettuce I've had bolt yet this year is the anonymous where-did-that-come-from leaf lettuce, now in the compost pile.

UPDATE: Except for necessary thinning, I've not yet harvested any of the lettuce in the experimental row, and it is doing well, except for the Jericho romaine, which is awfully small and undeveloped. I still attribute this to its being down in the floody end of the row.

The Nevada Batavia is showing a few slight signs of tipburn but otherwise looks just great and tastes great. Time to add more shade.

The Summertime iceberg is definitely heading and showing no signs of stress at all.

The Adriana butterhead, the few heads that are growing, is also doing well. I've been picking it from an earlier planting in April, and today I noticed one of the mature heads beginning to bolt.

Not part of the experiment, but the New Red Fire leaf lettuce from the same April seeding as the Adriana is also mature and still holding very well. It's been the backbone of my salads the last week or so.