Start Your Seeds Indoors This Autumn!

March 20, 2022

February is one of the hottest months of the year so now is a good time to start some of your Autumn sowings both outdoors and indoors. Sowing times depends on what district you live in but you can start seeds indoors roughly 6 weeks prior to planting.

Why start seeds indoors?

Vegetables such as carrots, radish and parsnip should be sown direct into the garden as they do not transplant well, where others can be started in punnets or containers, either outdoors in warm or temperate districts or indoors in cooler areas.

Many cool weather crops have a long growing season so it is a great idea to start them earlier in the year for healthy starts that are ready for transplanting at the beginning of Autumn. This is helpful for two main reasons:

  • Planting too late in Autumn and Winter will mean your seedlings grow very slowly. The day lengths significantly shorten and cold winter weather decreases the rate of growth.
  • You want your Autumn and Winter crops to fully develop and be harvested before Summer rolls around again. Hot weather and increasing day length can cause maturing crops to run to seed prematurely and may impact the quality (and taste!) of your veggies.

Some longer season varieties include the brassica vegetables such as Broccoli, Brussels Sprout, Cabbage, Cauliflower and Kale. Radicchio should also be started early, to ensure the plants are ready for harvesting in chilly weather which will help develop the richly coloured inner leaves and solid heads.  

There are also a lot of delicious leafy greens for Autumn which can be started indoors. Some great ones to try include spinachsilverbeetlettuce and Asian greens. Many of these plants can be harvested as needed, particularly loose leaf lettuces and silverbeet which means you won’t have to replant the crop each time.

Let's not forget onions. Try seeds of spring onions, leeks and shallots. For the tropics and the subtropics, your choices include all the warm season crops that gardeners in the south have to wait until next Spring before sowing.

Containers

Certain varieties don't like to be transplanted because of the shock to their root system. Jiffy is great for this because you can sow the seeds, then plant the whole thing, pot and all, without disturbing the roots. If using your own containers to sow crops, ensure they are clean and have good drainage holes.

If you are the DIY type try egg or milk cartons, yoghurt or paper cups. Some gardeners make pots from strips of newspaper so you are only limited by your imagination.

HINT: When using anything made of peat (much like our Jiffy products) wet the peat thoroughly first before putting in your seed raising mix otherwise the fibre or peat will act as a wick and pull moisture out of your soil.

Medium

You've got your container so now lets fill it; not with garden soil but some quality seed raising mix. A good seed raising mix is formulated for perfect drainage and water retention and often includes some slow release fertiliser for an added boost.

We recommend seed raising mix over regular potting mix because it's much finer for small seeds to germinate and establish. This is important because you want the mix to make good contact with the seeds to prevent them from drying out.

HINT: Always sow about twice as many seeds as the number of plants you want because sometimes (but not always) some of the seeds won't germinate and there can be losses in the transplanting process and again when thinning.

Location

When sowing into trays and pots either indoors or outdoors the location is quite important. Harsh direct sunlight and exposed windowsills can easily burn off delicate young seedlings so it is best to give them a bright area with filtered light instead to begin with.  

Once germinated you will want to harden off seedlings by gradually exposing them to more direct light and outdoor temperatures over a couple of weeks. Ensure they are kept well-watered in this time. 

When to Transplant

A good sign of when your transplants are ready for the garden is to check if the roots have filled out the pot. If you notice small roots through the drainage holes or out of the sides of your Jiffy pots it is a good sign. Alternatively, you can also very gently grab the stem (if it is sturdy enough) of the plant and if the pot easily releases with the roots holding soil then it is ready for planting.

If you keep your seedlings in small pots for an extended time they could become rootbound. The roots should be gently loosened prior to planting to allow them to branch out in the soil.


Looking for other Autumn vegetable seeds to sow? Click here to view our 'What vegetable seeds to sow this Autumn' page for inspiration and ideas.