Sowing Seeds into Punnets

Read on to learn how to sow seeds into punnets. I use this method for heat loving seeds such as tomatoes, capsicums, chilli’s, cucumber, zucchini, squash, (plus brassicas – broccoli, cauliflower, kale, cabbage, kohlrabi – who require a little TLC). In New Zealand, particularly the South Island, where we only have the three summer months of long hot days these heat loving plants require some assistance indoors to get started. I also direct sowing some seeds into the garden, find out more HERE.

How to Sow Seeds into Punnets

Early to mid august I organise my seeds, order what I need, and sow my punnets. Here is how I do it:

You will need:

Punnets/ containers (always hold onto empty seedling trays) – vines and creepers (tomatoes, zucchini etc.) don’t like being replanted too many times so sowing them into individual punnets is preferable.
Labels – always name and date seeds – ice-block sticks work well. I like to grow a selection of heritage tomatoes each season so naming helps determine what varieties are our favourite to save seed and grow again next season.
Seed raising mix – this can be purchased from garden centers. Or make your own: 1 part organic compost, 1 part leaf mould and 1 part fine sand.

What to do:

1. First decide what and how many seeds you are going to sow. For our family of four I plant around 8 tomatoes (4 medium/large, 4 cherry tomatoes), 2-3 zucchini, 6 cucumbers, half a dozen pumpkin/squash, plus several capsicum and chilli plants.
2. Get your containers and labels ready. Scoop the seed raising mix into the punnets/ containers. Tap to distribute soil evenly and pack firmly to a minimum 5cm soil depth. It is important the soil is packed evenly for proper water distribution.
3. Use your little finger to mark indents for the seeds in the soil. Now carefully drop two seeds into each indentation (I double up and use 2 seeds per hole as insurance). Sprinkle with extra seed raising mix so to cover the seeds by 2 times their size and gently press to smooth the surface.
4. Once all the seeds are sown and labeled, water them well with a fine-mist spray bottle (so not to disturb the seeds) cover with a dark plastic bag or newspaper and leave in a warm dark place to germinate. I put mine on top of the fridge where it is warm (hot water cupboards and heat pads are also a good option to ensure germination). Every few days check the soil is damp to touch, spraying with more water if needed.
5. Once the first shoots raise their heads remove the plastic bag/newspaper and place the punnets in a warm sunny position during the day to grow. If you take them outside remember to bring in at night so they don’t get too cold.
6. When the first two lateral leaves are formed (see photo below) you can prick-out any extra seedlings (choose the smaller plants to remove) so there is only one seedling per punnet/ container.
7. Once any sign of frost has passed harden-off the seedlings first by leaving in a covered-area outside overnight then in a nice sheltered corner of the garden.

Traditionally in the Top of the South (Nelson, Tasman, Marlborough regions) and North Island tomato seedlings are planted around Labour day (the Last Monday of October). The rest of the South Island and coolers areas in New Zealand are best to wait until the second weekend of November to avoid that possible last frost. The seedlings for planting out need to be at least 12cm high with a strong stem and good leaf development – that is why I start my seeds early as they can take 8 weeks to get to this stage.

I like to jump ahead a little here and get mine in a week or so earlier, using reusable 1.5 litre fizzy bottles with their bottoms cut off to cover the seedlings overnight (like a small cloche), taking them off during the day when the sun is warm. *Update 2017: we have since built a glasshouse from recycled windows to grow heat-lovers indoors, I now transplant tomato seedlings to the glasshouse late September/early October.

P.S. Here is  a little a video on how to save tomato seeds.