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Which is Better To Keep Cut Lettuce Fresh: Vacuum Pack or a Plastic Knife?

Preview: Which is the better to keep cut lettuce fresh? Is a plastic knife the answer or does vacuum-packing work better? Here is my answer. You might be surprised. Read my answer to this question I received from one of my readers.

It’s question time again, folks! In regard to the way I vacuum-pack lettuce into Mason jars, several people have left comments/questions about the use of a plastic knife to cut lettuce. They claim it deters brown cut edges, thus avoiding the need to vacuum-pack lettuce for those who desire to store cut lettuce long term.  

When I say long-term, I’m talking at least a week to 10 days.

The test:

I decided to test it for myself, so I chopped some hearts of Romaine with a plastic knife and some with a metal knife.

Is a Plastic Knife a Substitute for Vacuum-Packing Lettuce

I prepared three jars.  

The first jar contained lettuce cut with a plastic knife, stored in a securely-covered glass jar, but not vacuum-packed.

The second jar contained lettuce sliced with a plastic knife, then vacuum-packed.

I prepared the third jar the usual way I always do it–with hearts of Romaine lettuce, swiftly chopped with a metal knife, and then vacuum-packed.

Is a Plastic Knife a Substitute for Vacuum-Packing Lettuce? -- lettuce in the refrigerator

I stored these prepared jars in the refrigerator Sunday afternoon.

Is a Plastic Knife a Substitute for Vacuum-Packing Lettuce? --jars of lettuce in the test

The following Friday, I opened them to see the results.

plastic knife and lettuce results
Which lettuce would you pick?

Interesting, don’t you think?  The two jars that were vacuum-packed, both the one cut with a metal knife and one cut with a plastic knife, still look as fresh as the day I packed them. No brown edges. But that jar on the left, cut with a plastic knife, but not vacuum-packed?  Yuk!!

The answer to the question:  “Is a Plastic Knife a Substitute for Vacuum-Packing Lettuce?”

Looks like I won’t be needing my plastic knife after all since a sharp metal knife cuts faster and easier.  Indeed, vacuum-packing removes the oxygen so the edges don’t get brown no matter how you cut the lettuce.


Sunday 28th of December 2014

Honestly, this is way to much work. I just cut up my lettuce. Throw it in a big Tupperware bowl. Place several paper towels on top. Put the lid on the bowl. And then flip upside down and leave it like that in the fridge. Cucumbers, carrots, and all in the same bowl. It lasts at least a week like that. As long as you don't put it in the coldest part of your fridge. I do the same in smaller portions, in cheap Tupperware. Like 4 containers for $1. Give it a shot :) oh I also just pat the lettuce dry. I don't have a spinner.


Monday 6th of January 2014

I remember seeing this concept floating around fb a while ago, but the person demonstrating the technique gave a non-vaccum sealer option for those of us who don't have, nor wil we buy, a vaccum sealer. Have you ever seen/tried it?


Tuesday 7th of January 2014

Hi Dana, I'm not sure what you are talking about. You can always put lettuce in a quart jar without sealing it but it won't last as long in my experience. However, there are several ways to get a vacuum seal besides using a full-size vacuum machine. See this post and this post.


Tuesday 6th of August 2013

Hi, Paula. Firstly, please ignore my email. It was made by a friend in the 6th grade. Secondly, I have been following your blog for a while now, and I love that salads are kept fresh in a vacuum-sealed canning jar! I read of all the comments above and I am so excited to finally try my own salads in a jar, but because I like spinach and a lot of leafy greens in my salads, I am still hesitant to try it out. I was looking at this website:, and it tells me that spinach can last longer by storing it in the above mentioned way, but I was wondering if the spinach and the leafy greens are rolled up, as mentioned, and placed in a jar and vacuum-sealed, would that help keep the spinach fresh longer? You say you only carry it in the jars and eat in a bowl anyway, so if I were to roll it up (though a bit inconvenient during lunch time) and unravel the towels during lunchtime before placing it in a bowl, maybe that will keep it longer...? How long does the spinach last in a vacuum-sealed jar anyway?


Wednesday 7th of August 2013

Ray, Spinach is too delicate for vacuum-packing. At least, that's my experience.


Thursday 13th of June 2013

i definitely see a difference btwn the plastic and metal kinfe vac packed jars of lettuce. crispier for sure with the plastic and the metal slightly browned compared to the plastic. ive never bot a plastic knife but then again i never even cut up my lettuce. will this work with bagged precut/premade lettuces?


Sunday 3rd of March 2013

Where do I get one of those hand held pumps and the mason top one so I wouldn't have to prick a hole in the top of the jar? I don't want to invest in a food saver.