Oh, Minnesota. You definitely keep things interesting, from a gardener's perspective. Especially in spring.

Just two years ago, it was so hot and balmy in early April that experts had to caution us to resist the temptation to put hot-weather crops like tomatoes into the ground prematurely.

This week, we're looking at a weather forecast with a couple of dips down into the 30s. It'll feel "more like October than May," as meteorologist Paul Douglas noted.

So where does that leave us, in terms of spring planting? The old rule of thumb used to be to wait until Memorial Day. But in recent years, Mother's Day has become sort of the unofficial kick-off to the gardening season.

This year, the old model is probably the safest model, at least for certain plants.

Cold-hardy plants can handle a nippy spring. Cool-weather veggie crops like broccoli and cabbage thrive on it. But it's definitely too soon to plant tomatoes and peppers. If you've already bought those plants or grown them from seed, keep them inside a while longer. It's best to wait until the soil temperature reaches 50 degrees before putting them in the ground.

Tropicals and houseplants that you want to bring outside for the season also should stay indoors a while longer -- until there's nothing lower than 50 in the forecast.

What have you planted so far? And what are you still sheltering indoors?