How to sow perennial seeds in milk bottles

During July (mid-winter), I am sowing perennial seeds in milk bottles.

This process is called Winter Sowing and is ideal for seeds that require cold stratification (period of freezing temperatures to break dormancy) to germinate. The milk bottles act like a mini greenhouse, allowing light in and protection from the weather but also subjecting the seeds to freezing temperatures. 

Sowing in mid-winter means your seeds will get 6-8 weeks of frosts before the weather warms up in spring when they will gradually begin to germinate. It can be a lengthy process but one of those things you can just set and forget which is a ideal for those with limited time.

(I am following a Liz Stewart’s method from Flowering Flower Farm in Upper Hutt.)

How to sow perennial seeds in milk bottles:

1. Using a clean milk bottle, drill holes in the bottom and the cap.

2. Cut the milk bottle in half on three sides only, leaving one side intact which will act like a hinge for opening and closing the bottle.

3. Fill the bottom half with seed raising mix.

4. Scatter perennial seeds onto the top.

5. Close the milk bottle and use tape to secure it shut.

6. Label using a waterproof marker.

7. Bottom water to ensure the seed raising mix is thoroughly moistened.

8. Place the bottles outside in a sheltered area where they cannot blow away.

9. Do not let the soil dry out, you can test the weight of the bottle to give you an indication if it needs to be watered. Wet = heavy / dry = light.

10. Wait until spring for seeds to germinate and carefully prick out once seedlings have their first set of true leaves.