Most home seed starters know about the concept of “hardening off tomatoes” where we acclimatize our plants to the outdoors gradually. But what many gardeners don’t know – and this is another of those small commercial tips that make a big difference – is the exact nature of this hardening off process for tomatoes.
Way back when I first started growing tomato seedlings for market gardeners in our region, I did a ton of studying and reading about tomato seedling production. One of the things that caught my eye was the hardening off procedure and how it worked to increase the eventual harvest (or not). 🙂
Your Schedule For Hardening Off Tomatoes
Follow this rigorously. Here’s why. This is one of those small things that will allow your plants to move from the indoors to the outdoors without stress. And this is absolutely critical for both early tomatoes and the eventual harvest size.
You see, any stress at this point puts the plant into shock. It will recover but it may take it a few days (days lost to growing while it recovers)
You can’t see the shock – the plant slows down its metabolism and slows growth – and you may not even know it.
Here’s Your Schedule: (always assuming day time temperatures are in the high 50’s)
- Day one: One hour outdoors and out of the wind. The plant says, “What?”
- Day two: Two hours outdoors and out of the wind. The plants says, “Not again.”
- Day three: Three hours outdoors and out of the wind. The plants says, “OK. I get it”
It’s those first three days that make or break the harvest. And it’s this period that many home gardener skip – moving too fast through it.
- Day four: 5-6 hours – put in more open space.
- Day five: all day – in more open space
- Day six: all day, and all night in open space.
- Day seven: plant.
If the leaves turn a “silvery shade” – not burned-looking or white but silver – then you’re stressing your plant with too much wind.
Windburn. This plant (below) is now firmly stressed out It is not a great pic for the “silver” part but the leaf on the left below the browned leaf is showing silver.