March Greenhouse Gardening...

The Greenhouse Gardener's Diary - March

March can be cold and windy, but there may be a few calm days during the month. . Many flowers start to appear with the first signs of Spring and the Forsythia bush is in full bloom.

March is the time to:

Sow:

• Ageratum
• Nicotiana
• Nemesia
• Zinnias
• Stock
• Half hardy annuals
• Melon seeds
• Dahlias

Harden off :

• Outdoor tomatoes
• Cauliflowers
• Onions
• Leeks

Repot in fresh compost:

• Asparagus sprengeri
• Codiaeums
• Palms
• Smilax
• Begonias
• Ferns

Things to do:

- Start dahlia tubers by popping them into boxes containing moist soil or peat. Keep them in a warm greenhouse to encourage them to sprout and form new shoots, from which cuttings can be made

- Repot decorative plants in fresh compost

- Sew melon seeds singly, 2cm deep in small pots. Keep om a close atmosphere (temp: 18 - 20 °C)

- Pot on any tomato seeds sown during January and February. Keep the plants growing at a steady rate, but not too fast

- Harden off any outdoor variety of tomato plants, ready for planting out in June

- Ferns are starting to their growing period, and require a little ventilation, if the weather permits

- Harden off cauliflowers, onions and leeks which were sown under glass in January, in preparation for planting out in early April

- Keep an eye on pest control in your greenhouse

- Provide shade for young seedlings if necessary

- Ventilate your greenhouse and cold-frames, and make sure that they don't lack water