Updated October 2026
How to Preserve a Garden Glut in New Zealand
Bottled fruit, jam, chutney and a full chest freezer: here is which method suits each crop, and the one rule that keeps it safe.
Use a boiling water bath with a tested time for fruit, jam, chutney, vinegar pickles and tomatoes with added acid. Freeze low-acid vegetables such as beans, peas, sweetcorn and courgettes, or pickle them from a tested recipe. New Zealand Food Safety names low-acid foods as the usual source of home-canning botulism, and the overflow method many family recipes use has never been tested. The picker below suggests the best route for each crop.
Boiling water bath
Fruit, jam, chutney and tomatoes with added acid, processed for a tested time. Safer than overflow sealing.
Pressure canner
Needed for beans, sweetcorn, kūmara and meat in jars. Few New Zealand kitchens have one.
Sauerkraut
Cabbage and salt fermented at 16 to 24°C. The one vegetable ferment with a tested method besides dill cucumbers.
Chest freezer and dehydrator
Blanch and freeze, or dry at 60°C. The most practical tools for a humid climate.
Acid decides the method
At pH 4.6 or below, a boiling water bath is enough. Above it, botulism spores can survive in a sealed jar, so the food needs a pressure canner or the freezer. Vinegar sold in New Zealand can be as weak as 4% acetic acid under the joint food standards code, while tested pickle recipes assume 5%.
Pick your glut
Method guides
- Bottling passata and tomatoes: acid in every jar, 35 to 40 minutes in boiling water.
- Jam, jelly and marmalade: the 5 minute boil after filling.
- Pickling: tested brines, 5% vinegar.
- Sauerkraut: salt, a warm enough cupboard, 3 to 6 weeks.
- Freezing: blanching times and -18°C.
- Drying: 60°C, which beats humid open air.
- Pressure canning: why the overflow method never suits vegetables.
The New Zealand preserving calendar
January to March brings stone fruit, berries, tomatoes, beans and courgettes. Autumn is feijoas, apples, pears, quinces and the last tomatoes, which become green tomato chutney when the nights turn cold. Winter is citrus for marmalade and cabbage for sauerkraut. Southern regions run a few weeks behind Northland and Auckland. Find My Region sets the calendar for where you live.
Sources we checked (October 2026): New Zealand Food Safety (MPI), Clostridium botulinum or botulism; Food Standards Code Standard 2.10.1; USDA Complete Guide to Home Canning (2015) and the National Center for Home Food Preservation, including Equipment and Methods Not Recommended.
Common questions
Is the overflow method safe?
It has never been tested, and USDA lists sealing hot-filled jars without processing them as not recommended. Process jars in boiling water for a tested time instead.
What should I do with too many courgettes?
Blanch slices for 3 minutes and freeze them, steam grated courgette for baking, dry blanched slices at 60°C, or use a tested pickle recipe.
Can I bottle vegetables?
Only as tested vinegar pickles, or in a pressure canner. Freezing is simpler for most households.
How long do preserves keep?
Bottled fruit and jam about a year; dried food 6 to 12 months; frozen produce 8 to 12 months at -18°C.