Lollo Rossa

[zazen999]

Hi

I grow a few different lettuces; some cut and come again and some heading types.

Lollo Rossa, I grow lots of.

When they are in pots, they are green.

Within 2 days of being in the ground though, they turn red.

Even when I use soil that is taken from the garden and mix it with cheap compost to fill the pots - it still stays green and turns bright dark red once it is outside.

Even if it hasn't rained [I thought it was the rain that might be doing it] they turn red. I used rainwater on the ones in the pots and nothing changed.

Any ideas? It's not just a little red, these are dark purply red - in fact no green remains on them after 48 hours.

Just pondering on this chilly rainy June evening- I should be out on the decking watching the ducks but it's so windy and horrible.

[trebellangeminired]

Lollo Rosso is a "red" lettuce. I don't speak Italian but I think that's what Rosso means. I think the green version is called Lollo Blondo or something like that. We like the Lollo Rosso in salad but it may not be to everyones taste.

Just drying out myself and I only watered the greenhouse!

[Flummery]

It is always going to be red - only the young leaves are green. Lollo bionda is the green form. Some seed companies sell a mix of both which I buy whenever I see it. I do like the oak-leaf shape and the 2 interesting colours together.

[zazen999]

I know it is red - It's what changes the colour that is flummoxing me. The soil and rainwater being the 2 main culprits - it literally changes colour within 2 days of planting outside. The leaves that are green changes into red - it's not growing new red ones.

Very strange.

[jaykay]

I had some lollo rossa in the greenhouse and some in a pot right outside the greenhouse. The indoor plants grew faster at first but started to look a bit sad and lost their red colour as the temperature in the greenhouse increased. The outdoor plants kept growing steadily and retained the lovely dark red leaves. So, I wondered whether it was the temperature that was determining the colour!

[zazen999]

Possibly, but ours have been grown in the garage, which is less windy but not heated.

I've taken photos today and will do again tomorrow - would love to know what changes the colour so quickly.

[DavidJP]

I've noticed the colour change as well with Lollo Rossa and also with other red lettuce varieties and with redbor kale.

I suspect that the red colour is in response to a change in temperature. Maybe the colour is the plants response and some way of protecting it from damage. Many antioxidants, anthocyanins are coloured and often have some protective function.

I wouldn't be surprised if the gene that regulates the colour is temperature dependent and maybe the lower temp switches it on and hence you get the colour change. Forgive my background but you can create or select for mutations that are temperature dependent, which is quite convenient as then you can then alter the expression of that gene simply by changing the temperature. This technique is used quite a bit in genetics, I suspect that the red lettuces were stumbled upon by someone selecting for red colour which may have a protective function in the wild and that many of these colours are driven by temperature dependence, which in of itself may be an adaptive response in wild lettuce but by slection has been driven to extreme.
Just a theory and I have no evidence at all but I've been wondering about the same thing.

David

[zazen999]

Interesting, would be worth trying some in pots here, in compost and in soil; to see if the temperature indeed makes a difference. Obviously growing them outside in similar conditions, rather than indoors.

due to sow some more soon so perhaps I'll do just that.

[c00kiemonster]

Im growing lollo rosso outside in a container and I'm finding with mine that only the tips of the leaves are turning red, whilst the rest remains green!

Was unsure myself was makes them go red.
Still it tastes very nice tho

cm

[trebellangeminired]

Sorry, I didn't understand the question However you have made me aware of something I might have put down to my incompetance. I sowed Lollo Rosso, Cos, All the year round and little gem in the greenhouse under the potting bench for the first time this year, the idea being that they would be protected from pests and weather. However the growth initially for all except the Lollo Rosso was soft and pappy but has since improved because they have been treated as a cut and come again. The Lollo Rosso took ages to germinate and were way behind the others. Now they have started to catch up and as you observed they are mostly green. It would be easy to assume that the higher temperature affects the colour as well as germination although my follow-on outside sowings have had varied results. The Little Gem and All the year round have come up well but only two of the Cos and none of the Lollo Rosso have germinated. It's a work in progress

[zazen999]

Hi

The question was only, what makes them turn red? Inside = green; outside = red.

Still under investigation...

[DavidJP]

I think I may have come across the answer. If you do a google search you can find patents for red lettuces and if you read them it suggest that the red colour (anthocyanin) is induced by UV radiation. In other words not temperature dependent but by being outside, in a greenhouse glass absorbs short wavelengths of light and so no red colour is induced. I suppose the red colour has been selected as a by product of the plant producing red colour in response to damaging UV radiation.

(WO/2007/039137) RED LETTUCE

Anthocyanin synthesis in lettuce is induced by UV-radiation

So next expt would be to paint one half of a Lollo Rosso with sunblock the day before you put it outside.

[trebellangeminired]

I over-wintered a batch which turned red in a greenhouse with a small heater designed to keep the temperature above freezing or could it be that they were in there so long they absorbed enough UV even through the glass? They were watered with rainwater and grown directly in the greenhouse border in a mixture of home-made compost and well-rotted manure.

[Tracey]

I had the same experience with my Lollo Rossa. In the potting shed they were all green with red streaks. I planting half outside and they turned dark red overnight. The rest in the potting shed stayed green/red. When I eventually planted those out a week later, they too turned dark red overnight. The colour didn't protect them from slugs though, they still got eaten