What to do in the garden this week

Very hungry monarch caterpillars

It’s not too early to plan how to keep monarch butterfly caterpillars all fed.

‘‘Most people wait until they see a monarch and then buy teeny plants in the garden centre, which will only feed a couple of caterpillars,’’ says Jacqui Knight, from the Moths and Butterflies of New Zealand Trust (MBNZT).

‘‘If you sow seeds this month, you won’t have to rely on bought swan plants to feed hungry caterpillars later in the season.’’

Swan plant seeds are available from garden centres, Kings Seeds and MBNZT, or you can grab a mature seed pod from a plant that has overwintered.

Seeds need soil temperatures of 21-24C to germinate, so plant in seed trays undercover or in trays in a sheltered place outside if it is warm enough. Transplant into the ground before they are too big (under 20cm) as the roots don’t like to be disturbed.

And plant lots! Those hungry monarch caterpillars can munch through a young plant in no time. It’s a good idea to cover a few of your plants with netting to prevent eggs being laid on them. This means you will have food when the other plants are stripped bare.

Nip out the growing tip of each stem just above a node, so the dormant buds there will develop into stems resulting in a stockier, multi-stemmed more compact plant, which may provide a little shelter and protection from wasps. Watch out for slugs and snails, which can chew through a punnet of seedlings or ringbark a larger plant. Orange aphids are another nuisance. Don’t spray plants with insecticides as this will kill the caterpillars too. Instead, squash them with your fingers, give them a blast with the hose or carefully spray with soapy water.

Keep it clean

Nothing is more disheartening than seeing a promising punnet of seedlings suddenly wilt, collapse and die.

The problem is a fungal infection called damping off and it’s most likely to occur in wet, cool conditions.

To reduce the chances of damping off wash punnets before reusing them and rinse with a mild solution of bleach.

Always use fresh seed raising mix. Keep the soil mix moist but not saturated – let them drain after watering and don’t let them sit in a puddle of water. While you’ve got the bleach out to clean your seed trays, give paths, steps and decks a wash and brush up too.

A mild winter with plenty of rain has turned my shady back path and wooden steps green with moss, and the sloping concrete drive could double as a slip and slide.

In the past I’ve used a water blaster, 30 Seconds or Wet&Forget but a stiff broom and a bucket of diluted bleach does the job and gives one an energetic workout too.

Scrub out the bird bath and give bird feeders a good clean as avian diseases can spread quickly through bird populations when they congregate.

Be careful about cleaning nesting boxes as they may be in use already or prospective parents may be checking out their new home and you don’t want to frighten them away with intrusive housekeeping.

Ready, set, sow – seeds to start now

Punnets of seedlings from the garden centre are great if you only want a few plants of each variety and you’re happy with a limited range of popular varieties. On the whole, there’s enough choice and the seedlings are generally of very good size and quality so there’s an excellent chance of newbie gardeners having success.

On the other hand, growing from seed is much cheaper if you need a lot of plants and there’s so much choice of interesting varieties to try from tried-andtrue heirlooms to the latest disease-resistant offerings from the plant breeders. Plus, it is so satisfying to watch your seed babies grow day by day.

Now is the time to sow tomatoes, eggplants, chillies, capsicums and pumpkins in punnets or trays indoors. These heat-loving crops need a long season to ripen but the ground is still too cold to sow their seeds directly outside. Giving them a head start indoors means you’ll have big established plants by the time it is warm enough for them to be transplanted outside.

Start with clean containers and fresh, moist seed-raising mix. Check seed packs or Kings Seeds for the correct sowing depth. Cover with newspaper to keep the mix moist but remove it when the first seedlings appear. Keep warm – the top of the fridge or underfloor heating both work well.

Seed trays are handy for corralling sets of punnets together. It’s a quick job to lift a batch in and out of a water basin or out into the sun when hardening off. Lining the tray with old towelling or newspaper acts as a moisture reservoir.