Start your seed library

Some gardens may have experienced their first, light frosts and all gardens will be seeing a slowdown in growth rates. I enjoy this time, as growth is not so frantic, pest numbers are decreasing and rain is more frequent – meaning less time spent watering.

The autumn to-do list

Go on pest patrol. During these autumn months it is important to remove any fallen or diseased leaves as these are potential hiding places for pests who use this organic matter to overwinter in. Remove and bury or burn any leaves covered in grey fuzzy mould. This is most likely a fungal infection. You can spray the affected plant with copper or sulphur to make the fungi retreat.

Protect plants from birds. Young lettuce, silver beet and broccoli are especially at risk. Cover seedlings with wire netting or bird netting.

Collect fallen leaves for compost. If you can source some jute sacks from coffee shops, fill these with leaves, tie up the end and leave in a shady spot to mature over winter. Come spring you will have a beautiful leaf-mulch that’s rich in carbon and great as a general soil improver.

Planting now

All the winter brassicas can be planted out in central and northern areas of New Zealand. Plant broccoli, Brussels sprouts, cabbage, cauliflower, celery, leeks, lettuce and silver beet.

Plant carrot from seeds. The trick for an even and good germination of carrot seeds is to ensure the seeds are fresh and the soil is constantly moist. After planting I water well and then place a wooden board over the area to conserve moisture. Obviously remove the wooden boards when you can see some young shoots. Plant spring onions, leeks and onion.

New crops to try

If you want to grow some less-common types of vegetables over winter, here are two suggestions

Kohlrabi is a member of the brassica family and like most brassicas it is full of healthy antioxidants. It looks a little bit alien with its swollen round green stem and leaves shooting off in all directions. All parts of the plant can be eaten. When young the leaves are great in stir-fries, while the swollen root can be eaten raw or cooked – it has a similar taste to a broccoli stalk.

When you cook with kohlrabi it’s important to peel the root thoroughly. Beneath the thick, hard skin is another fibrous layer, which should also be peeled away.

Grow kohlrabi in full sun and in rich soil over the colder winter months. Now is a perfect time to get some started in your garden.

Curly leafed kale has become known as a super food and is said to have many health-giving benefits – it’s a source of fibre and high in vitamins A, C, K and antioxidants.

I love growing this plant over the winter months. It is easy to grow and looks spectacular on a cold morning with its crinkly edges dusted in frost. The frilly leaves are very ornamental in their own right.

Grow kale in full sun, in soil which has had a recent feed of compost, blood and bone or sheep pellets. Wait for the first frosts before harvesting as this makes the leaves even sweeter.

Start saving seeds

If your garden is looking like some dried flower arrangement at the moment, don’t despair – you may actually be looking at the potential seeds for next season’s garden! By saving seeds you become that much closer to self-sufficiency as you are less reliant on shop-bought seeds.

To get started, let a few plants of the type you want to grow again go to seed. You may want to choose a variety that you particularly enjoyed eating, or those that were most pest-resistant or that still grew with little watering or care. By choosing these you are breeding plants most suited to your environment and lifestyle.

If you have been growing hybrid plants, just a word of warning – they won’t produce seeds that develop exactly as their parent. Hybrids or F1 plants have been crossbred for certain characteristics so the seeds are often not true to the parents’ characteristics and revert back to the original stock. Many seedlings that are bought from garden centres are hybrids. Look out for the word hybrid or ‘F1’ on the label when you are buying them.

How to start

Let the seeds dry out completely on the plant until the seed pods are brown and starting to split. If you shake the pod you should be able to hear the seeds rattling inside. Harvest seed on a hot, dry day, around midday so that any morning dew has dried. Beans and other large seeds are the easiest to collect. Small seeds may need to be shaken in a sieve. This helps to separate the seed from the husk.

I often put seed heads in a paper bag and peg the bag to the washing line for the day. This helps to drive any remaining moisture out.

Storing seeds

For long-term storage you need to separate the seed from the husk as the husk may harbour pests which can feast off your carefully stored seeds. An easy way to separate small seeds from their outer husks is to winnow them. Choose a day with a gentle breeze. Lay an old white sheet on the ground, raise the bowl of seeds and husks above your head and pour into a lower, bigger bowl lying on the sheet. The breeze will help to blow and separate the husks from the seeds. The seeds are heavier so will fall into the lower bowl and the husks will be blown away.

When you collect any seed, place them in the freezer for 48 hours – this will kill any stowaway insects which could eat the seeds when in storage. Store seeds in paper bags or paper envelopes and label well with variety and date collected. Store in a cool, dark place. It is best to plant the seed the next growing season as some varieties don’t keep very long.

Harvesting seeds contained in a pulp

Seeds of tomatoes and cucumbers are contained inside a fleshy pulp. To save these sorts of seeds, firstly choose the best fruit from the plant and scrape out the seeds within the pulp with a teaspoon. Place this pulp in a glass jar and half full with tap water. Leave on a sunny window sill for three days. During this time the pulp will start to ferment and a thick froth will collect at the top of the water. After three days the viable seeds will have sunk to the bottom of the jar. Drain and dry on a paper towel. I then simply label by writing on the paper towel then roll up the paper towel and put it in a container. When you are ready to plant you can just tear off sections and plant seed and paper together in the soil.

Tips for storing seeds

• Store in a dry and cool place. Humidity and warmth will shorten a seed’s shelf life.
• Use sealable plastic bags, film canisters, medicine bottles, or glass jars with a screw-top lid.
• To keep seeds dry, wrap three tablespoons of milk powder in some tissue paper and enclose with the seeds. Save all the silica gel packets from medicine and packaging for the same use.
• Use a large ring binder folder with plastic envelope sheets to store seed packets – they’re then easy to catalogue and find.
• Always date your seeds. Most only last three years so you will know at a glance which ones need to be planted first.
• Exchange seeds with friends and neighbours to build up your library of heirloom plants to grow each year.