Red vs Green Lettuce: What Do Slugs and Snails Really Like?

Luckily this snail was exploring the possibilities of compost digestion before deciding to attack my lettuce 'Amaze'. ...Or was it?
As reported previously in August's Salad Days, we've been having an interesting #saladchat on Twitter recently about the seeming aversion slugs and snails have to red lettuces.

The majority of you reported this is so with the varieties you've been growing this year. This is a top tip, particularly for any wet year which leads to a population explosion of these pesky pests. Resistant varieties particularly mentioned were Red Salad Bowl and Dazzle.

Others said they hadn't noticed any difference, or indeed their slimy populations seemed to prefer red varieties such as Lollo Rosso, so it seems it's not quite as simple as red vs green. @littlesaladco said he'd found sappiness and leaf thickness was important, with the more sappy, thinner leaved varieties being preferred.

During this conversation, I vaguely remembered something I'd studied in A Level biology, where slugs  showed an aversion to plants producing compounds from the cyanide family (thankfully not enough to be poisonous to us!). I believe this is what Alys Fowler was referring to at a talk I went to earlier in the year when she mentioned lettuces produce bitter tasting compounds when nibbled. It's a defence mechanism which usually prevents further eating: probably not enough for a wet year like this one with slugs and snails in abundance though :/

Then came the breakthrough. Zoe Lynch came back with a reference showing the presence of anthocyanins in red lettuces might be a key factor. I'm also wondering if these levels are higher in sappier lettuces irrespective of their colour. Of course there may be other factors at play, all contributing to a sliding scale of nicer tasting  (probably sweeter) and juiciness, with mainly red at one end (not so palatable) and mainly green (oh so tempting) at the other.

Some saladchatterers said they found red lettuces weren't as nice as green ones, as they tend to be more bitter tasting. It looks like it's not just our pesky pests which have a preference for sweeter tasting, generally greener lettuce ;)

With thanks to Annemieke who originally posted the comment which led to our conversation on #saladchat. Also thanks to the people mentioned above plus @CarlLegge, @CountryGate, @karlasparlour, @maogden, @nicelittleplace, @PatientGarden, @Swanimages, and @wellywoman for joining in the conversation.

I feel the need for some field trials next year :)

NB I also found some other references around this subject if you're interested:

Comments

  1. Anonymous7 September 2012 at 12:31

    Fascinating. Thanks ever so much for this. Perhaps the answer to bitterer leaves is a sweeter dressing.

    ReplyDelete
  2. Dani7 September 2012 at 15:56

    Slugs prefer the green lettuce in my garden - the red, thankfully, they have left alone so far this year..

    ReplyDelete
  3. Andrea8 September 2012 at 13:09

    Slugs and snails might have a preference but rabbits certainly don't care, anything goes! I wonder if its the same with green and red cabbages?

    ReplyDelete
  4. Liz9 September 2012 at 12:53

    Now this I have to test. I have seedlings of both salad bowl red and salad bowl green, perhaps I'll plant them side by side in a known snail area and monitor the results - of course I may end up very sad and with no lettuce but at least I'd be wiser for it I guess.

    ReplyDelete
  5. Unknown9 September 2012 at 22:19

    It seems completely random in my garden. They demolished the spinach, ate most of the rocket but ignored a whole row of green lettuces. The lettuces were quite boring and didn't have much flavour anyway. Perhaps slugs do have some good taste then!

    ReplyDelete
  6. Janet/Plantaliscious10 September 2012 at 09:38

    Oooh, that is interesting. I wonder if this carries through to oriental leaves. Weirdly, my red Pak Choi seems to be being nibbled more than the golden form, which is also growing away more strongly. You almost tempt me back to twitter - get the behind me! It took over my life, I have no willpower...

    ReplyDelete
  7. Helle (Helen)12 September 2012 at 09:34

    The slugs in my garden are generally not discerning at all, but I have also noticed that they tend to leave the red varieties alone, or at least only eat them if there is nothing else around. But it's probably correct that they like the bitter ones less, I have a green one, can't remember the name right now, but it's slightly bitter and I never see any slugs on it. They might happily hide under it, but they don't nibble. Or devour.

    ReplyDelete
  8. VP20 September 2012 at 10:04

    Helen - that's a good idea. I also need to do some further research on the cause - a book I'm reading at the moment mentions a couple of compounds associated with bitter taste. I need to find out whether they're the specific names for the more general ones I've referred to in this post.

    Dani - welcome! Another vote for the red ones.

    Andrea - yes the topic of rabbits (and deer!) changes things massively. Luckily I have neither to deal with. @Carllegge also speculated the same re cabbages. I can't say because I've only grown red ones! What's your experience?

    Liz - that's exactly what I'm hoping to do next year. Perhaps we could compare notes next year :)

    Claire - welcome :) It seems your slugs prefer stronger, more peppery tasting leaves!

    Janet - they're certainly trying to have a go at the oriental leaves I've just sown. But then, the Amaze lettuces next to them have now transformed into a totally red lettuce since I took the photo. If you do get back on twitter, my chatty id is @malvernmeet and I'm always happy to have a #saladchat :)

    Helle - let me know if you remember the name of your resistant green lettuce, it would be great to add it to the trial

    ReplyDelete

New comments are not allowed.

Your essential reads

That blue flower: A spring spotter's guide

Image
Spring is a prime time for blue flowers and my daily walks currently have several from the same plant family* lining the local footpaths. As I walked past the Donkey Field the other day, I overheard some children ask their parents** what the pictured blue flower was. It reminded me it's often mistaken for those other familial blues and this time was no different, as they said it was forget-me-not, instead of the green alkanet it actually is. As well as similar flowers, most of these plants are hairy in their nature, flower around the same time, and favour damp, shady places. Many of them are great for pollinators too, especially bees and this week's warm weather has certainly drawn them to these flowers. This makes it even more likely for these plants to be mistaken for each other and it's a great opportunity for me to put together a spotter's guide in case you find the same flowers on your outings. Staying with green alkanet, the key features which set it
Read more

Jack Go To Bed At Noon

Image
Last year this rather exotic looking flower appeared on mine and several other allotments for the first time. Having been stumped (again) by Mr Allotment Warden as to its identity, I rushed home to find out what it was. It's salsify, aka the marvellous Jack Go To Bed At Noon - named as such because its flowers always close by midday. Here you can see both open and closed flowers - making it seem even more exotic and alien than in the first picture. I think this must be the cultivated version because the flower in my Francis Rose Wild Flower Key looks exactly the same in form, but is bright yellow in colour and called meadow salsify . Its other common name is Goatsbeard, which must be a nod to the fantastic dandelion-like clock which forms the seed head. With 'parachutes' like those shown above, who knows how far our plotted plants came from. I rather like the photographic dissection of the seedhead found in this link . Salsify is edible: its lateral shoots and fl
Read more

Red Nose Day - Gardening Jokes Anyone?

Image
The nation goes ever so slightly bonkers on Red Nose Day - hurrah! Previously, it's been very easy to join in - usually via a dress down day at work plus lots of people up to mad things at the station and in the office. Everyone smiling for once - it's a real feel good day and all in a good cause. This year's different - every day's a dress down day for me now - my friend L suggested yesterday that perhaps I could have a dress up day instead and whilst that's a good idea, I confess that ballgowns and tiaras don't really feature in my wardrobe: scruffy student's always been my favourite look. So my Red Nose Day contribution for this year is to compile a list of gardening related jokes. For each one (clean ones only please) you leave in the comments below, I'll make a donation of 50p to the cause. Here's a few for starters just to get you warmed up: Q Why do potatoes make good detectives? A Because they keep their eyes peeled. Q What did the grape
Read more

Salad Days: Mastering Lettuce

Image
I've decided one of my salad challenges for this year is to grow as many lettuce varieties as I can, ready for the publication of my planned Factsheet* later on. The idea is to grow as many of the Tried and Trusted lettuce varieties last year's Salad Challengers helped compile, then provide a visual guide and as many lettuce facts as I can muster. So far I've found around half of those listed**. Then naturally whilst I was out searching - because such is the way with seeds - a number of other varieties found their way home too ;) A couple of weeks ago I sowed 22 varieties***. Just the simple act of sowing them has me intrigued. Why are some lettuce seeds black and others white****? They split into about half white to half black in my sample and as far as I can tell it's nothing to do with whether they're a type of cos, iceberg, or whatever. I sowed them indoors and popped them into a propagator on the windowsill. The soil's too cold outside for sowing
Read more

VPs VIPs: Derry Watkins of Special Plants

Image
Last week I had the pleasure of visiting Derry Watkins at her home, garden and nursery - the acclaimed Special Plants - just a few miles along the road from me. I first met Derry at one of her open garden days last year and was keen to find out more about her wonderful garden and running an independent nursery. She specialises in tender perennials and regularly goes on plant hunting trips to find new treasures, particularly in South Africa. As well as running Special Plants and opening her garden under the NGS scheme , Derry holds day courses at her nursery, hosts Special Tuesdays from April until September, lectures and has written a couple of books. How did you find your way from Connecticut to the UK? I'd started a biodynamic vegetable garden in Connecticut and we used to have people come along at weekends to help out. A particular young man turned up: he returned many times and at the end of the summer I married him. So it was all down to love? Isn't that the
Read more

#mygardenrightnow: heading into summer with the Chelsea Fringe

Image
Ahhhhhh, that's better! I love walking through dewy grass in bare feet, not that there's much in the way of grass on my back lawn this weekend. My wild and woolly lawn has morphed into meadow of sorts this month, which even NAH admits looks attractive*. It's also proved a great source for my Flowers for mum project so far, yielding self-sown perennial cornflowers, lamb's ears, and lemon balm in addition to the blooms you can see. These originated from elsewhere in the garden, the ox-eye daisies must have blown in from the A350 nearby. * = he got very stroppy about the weeds aka self-sown foxgloves in the lawn one year, so he's come along a bit since then. Skimble's demanding to say hello to you too. He does enjoy the patio when it warms up. If the embedded video doesn't work try this link instead. The Nectaroscordum are a revelation. I planted the bulbs around 2 years ago, but it's only this year they've bloomed properly. The bee
Read more

The Resilient Garden

Image
  Part of Tom Massey's Resilient Garden at RHS Hampton Court I've been pondering VP Gardens a lot lately. Last year's drought conditions set me off initially, then our harsher than usual winter combined with this summer's flip and flop weather means the thinking continues. It's a huge topic which I freely admit I'm struggling to get my head around. Tom Massey's Resilient Garden  at Hampton Court recently  tackled this topic brilliantly and was a timely interlude which gave me much food for thought. There he encapsulated the detailed research he'd found which informed both his show garden and book of the same name. I think it's one of the most important show gardens I've ever seen. It's clear the way I garden needs to change so that I have my own resilient garden. I haven't worked out the exact details yet, but Tom's book plus a couple of others (see below), alongside the rainwater management handout from the show garden's  sponso
Read more

Testing Times: Tomatoes

Image
  I've run a couple of tomato trials this year. The first is a revisit of the biochar trial with Oxford University I attempted some years ago (with a different organisation this time), and the second is a trial of a water gadget called Plantsurge which I was given to try at Malvern Spring Show earlier this year. Most of you have probably heard of biochar already and the claim that this inert, carbon-rich material can help soil fertility and plant health. The RHS information in the above link says results can be mixed, with reduced effects found in alkaline soils. This may help to explain the lack of difference I found in my previous trial as VP Gardens is on a lime-rich soil. Plantsurge is a different beast altogether. It's a strong magnet which is attached to a hosepipe as shown in the photo above. It's claimed that it softens water, with the result more like watering with rainwater. The higher nitrogen found in rainwater is thought to be beneficial to plants. Gardener
Read more

Chelsea Fringe 2014: Shows of Hands - Episode I

Image
The gloves NAH used to build the raised bed . The effects are L to R, top to bottom:  Original photo, Warhol, HDR, Green tint, B&W, Posterize, Boost, Cross process and Sepia Welcome to Shows of Hands - my Chelsea Fringe project for 2014! As you can see I've been having a bit of a play around in Pic Monkey for my first contribution. You're welcome to join in between now and 8th June 2014. The idea behind this year's project is to highlight the tool most precious to a gardener: their hands. How do I take part? It's simple. All you need to do is take a photo of hand(s) in a gardening context and then share it via your blog or other social media (such as Twitter or Facebook), then make sure I know you've done so. I've set up Mr Linky below for your blog contributions. The Chelsea Fringe photo on the right sidebar links to this post, so you can easily find it again when you're ready to add your contribution. If you share your photo on Twitter,
Read more

Make Use of Mildew

Image
On my garden patrol this morning I spotted some powdery mildew on a couple of my new Verbena bonariensis plants. I suppose it was almost inevitable as I prefer to grow my plants hard - this means no water for them unless they look absolutely desperate. This approach means plants root themselves more deeply and have a better chance of survival during spells of dry weather like we've had lately. However, it also means I run the risk of problems like today's, especially with any garden newbies planted late in the season. We've had a good drop of rain overnight, so this should help my plants survive. I'll mulch them later today to help lock in the moisture as it's water stress which encourages the mildew to take hold. I've also removed the infected leaves and sprayed the rest with a milky drink.* I'm also pleased to find there's a use for my infected leaves. Oliver Ellingham at Reading University has started a PhD - sponsored by the RHS - researchi
Read more