Harden Off Gardens · frost
A frost warning at nine at night, and forty minutes to do something about it.
This is the page to open when the forecast turns. It is written for somebody standing in a garden in the dark with a torch, so it is short.
Cover these
- Tomatoes and peppersAnything below 40°F sets them back. Below 33°F kills them outright. These are the ones worth going outside for.
- Cucumbers, squash, beans, basilSame. Basil goes black at 40°F and there is no recovery.
- Anything planted in the last weekRoots that have not taken hold cannot pull water, and frost damage is really a water problem.
- Hanging basketsDo not cover them. Carry them into the garage. It is quicker and it works better.
Do not bother with these
- Pansies, kale, spinach, onionsThey are fine. Several of them taste better afterwards.
- Established shrubs and treesA late frost may take the new leaves off a Japanese maple. It will not take the tree, and there is nothing you could have done anyway.
- Anything in the ground since March that has been through a frost alreadyIt knows what it is doing.
- Your lawnPeople ask. No.
Use a bedsheet, not plastic
Frost damage happens where the cover touches the leaf. Plastic conducts cold straight through at every point of contact, so a plant under a bin bag often comes out worse than one left alone. Cloth does not, and an old sheet or a towel is the right tool.
Drape it to the ground so it traps the warmth coming out of the soil, which is where the heat is. Do not tie it around the stem like a bag, because that seals the warm ground away from the plant and leaves the leaves out in it.
Take it off by mid morning. A cover left on a sunny day cooks whatever survived the night.
Hardening off, which is the other half of this
- Day one and twoTwo hours outside, in shade, out of the wind. Back inside.
- Day three and fourFour hours, with an hour of morning sun.
- Day five and sixMost of the day out, in full sun, in still air. Inside overnight.
- Day sevenOut overnight if nothing below 50°F is forecast.
- Then plantEvening, not midday, and water it in even if rain is coming.
A plant that goes from a greenhouse bench to open ground in one step loses a fortnight even when nothing kills it. Everything we sell has been on an outdoor bench for at least a week before it reaches you, which is where the name of this place comes from.
If you are not sure, ring
Somebody here has been watching this forecast all day and will tell you plainly whether it is worth going out with a sheet tonight.
Call 816 555 0166