A frost warning is not one answer, it is seven, one per night. Checking GardenBuddy.au’s Frost Risk tool against postcode 7030, Waddamana in the Tasmanian highlands, this week turned up exactly that pattern: a frost likely night, then two clear nights, then frost likely again. Here is how a real gardener reads that table and decides what to actually do with it, cover tonight, plant Friday, or hold off.
Under two minutes on reading a real frost week and deciding what to do with it.
The situation
Say you have tomato and capsicum seedlings hardened off and ready to go into the bed this week, in a cold-climate postcode like 7030. Before digging a single hole, the question is not “is it cold” but “which nights, and for how long.”
What the tool actually showed
Checked live against postcode 7030 this week, the seven day table read:
- Thursday: 0°C, Frost likely
- Friday: 10°C, No frost risk
- Saturday: 5°C, No frost risk
- Sunday: -1°C, Frost likely
- Monday: 0°C, Frost likely
- Tuesday: 3°C, Cold, cover seedlings
The verdict line above the table summed it up as three nights at 2°C or under in the coming week, lowest forecast minimum -1°C. That is the number that matters before touching a trowel, not the single “is it cold tonight” question.
Why it matters
A single cold night does not make a cold week, and a single mild day does not clear the risk for the week either. Tender crops, tomato, capsicum, basil, beans, cucumber, zucchini and pumpkin, can go from thriving to blackened leaves in one frost night. Planting into the Friday or Saturday gap looks safe on the day, but seedlings put in Friday still have to survive Sunday night’s -1°C three days later. Reading the whole week, not just today’s number, is what actually protects the plants.
How to use it for this decision
- Check three to four days out, not the night of. The table runs a full week ahead, so a frost night shows up while there is still time to plan around it.
- Not planted yet? Wait for a clear run, not a clear day. One mild day between two frost nights is not a safe planting window. Look for at least several clear nights in a row before putting tender seedlings in the ground.
- Already in the ground? Cover, don’t wait it out. On any night tagged Frost likely, Frost risk, or Cold, cover seedlings, put a sheet, shade cloth or an upturned pot over tender plants before dark.
- Take covers off in the morning. A cover left on all day traps heat and moisture the plant does not need.
- Treat “Cold, cover seedlings” as the safer read. Forecast minimums are measured in the open at screen height. On a still, clear night the ground and low leaves sit two to four degrees colder, so a mild looking forecast can still mean ice on the lowest leaves.
Frequently asked questions
What if the week looks mixed, like this one did? Go by the worst night in the window you care about, not the average. A week with one frost likely night and five clear ones is still a week that needs a cover plan for that one night.
Does a mild Friday mean it’s safe to plant? Only if the nights after it stay clear too. In this postcode’s case, Friday and Saturday were clear but Sunday swung straight back to -1°C, so a seedling planted Friday still needed protecting three nights later.
How is this different from just checking a last frost date? A last frost date is a rough seasonal guess. This tool is a real seven day forecast for your postcode, checked fresh each visit, which is what an actual decision this week needs. For the seasonal side of planting timing, GardenBuddy.au’s growing guides are written per climate zone.
Related features
- The Frost Risk tool itself: the full walkthrough of what the four risk tags mean and where the numbers come from is covered in GardenBuddy.au’s Frost Risk guide (in the works, not yet published).
- Grow Zone Map: find your climate zone so seasonal advice elsewhere on the site matches your actual conditions.
- Veggie growing guides: zone-based planting windows that already keep tender crops clear of the usual frost months.
- Farmers Almanac: the longer range, month-by-month view for planning a season ahead rather than the coming week.
Try it now
Head to gardenbuddy.au/frost-risk/, type your postcode, and read the week the way this walkthrough did: the clear nights for planting, the cold nights for covering. It costs nothing and takes a postcode, that is all. Brought to you by the GardenBuddy.au team.
