What Can You Store in a Garden Shed Over Winter?
Obviously, hand tools can easily handle winter cold (it may be helpful to brush any metal surfaces with oil to prevent rust, whether you leave them out or not). However, if your shed will be made inaccessible by snow buildup, it may be wise to move some pruning tools into the garage or the house (secateurs, pruning saw, long-handled pruning shears, etc.): they could be useful if – heaven forbid! – shrubs or trees suffer winter damage. Also, fruit trees are usually pruned in late winter, so you’ll also need those tools on hand. Power tools too (mowers, trimmers, etc.) can stay in the shed, but read the instruction manual to see if there are any specific recommendations. Freezing can, for example, to reduce the useful life of some batteries and they may need to be stored indoors.
What about grass seed? When properly stored, grass seed is probably viable for at least 2 years, but if it is exposed to freezing, its germination rate may decline more quickly. It’s probably best to bring it indoors for the winter, storing it in a cool spot. Mycorrhizal fungi products also remain in better condition when stored free of frost.
Fertilizers can theoretically withstand freezing, but… liquid fertilizers will expand as they freeze and this can crack their container, leading to their loss, so are safer stored indoors. You can leave dry fertilizer in the shed during the winter. Note that, over the years, dry fertilizer can cake up. This is caused by condensation and will happen both indoors and out, although condensation can be greater in a garden shed and may therefore happen more quickly. Caked fertilizer is still usable: just crumble the cake into powder before use.
With any pesticide, always read the label: if it says it should be stored cool and dry, but there is no mention of “in a frost-free place”, you can leave it in the shed. In general, dry pesticides (powders, granules, etc.) will withstand frost. However, just like dry fertilizer, can also cake up and will then be more difficult to use. Liquid pesticides can crystallize, coagulate or come out of solution under the effect of freezing and should always be stored indoors.
Finally, in general, any soil or soil amendment (planting soil, compost, peat moss, etc.) can remain in the shed during the winter.
As for other products (and who knows what you have stored in your garden shed!), read the label or instruction manual: if it should be stored in a frost-free place, it should say so.