Success with seeds from sowing to transplanting

Success with seed sowing

Sowing seeds seems to scare some new gardeners, but once some basic skills are mastered it’s a very satisfying thing to do.

Putting seeds into a garden bed where you intend them to grow to maturity is called direct sowing. It is the recommended method for root crops (carrots, parsnips) and plants that don’t like root disturbance such as coriander. It’s the easiest and quickest method too, so start with raring-to-go radishes to get your hand in, then give seed sowing in trays or punnets a go.

Tiny seedlings do need care, but here’s how to increase their chances of growing into sturdy transplants.

Don’t skimp on seed raising mix. Fresh mix is ​​weed free, retains moisture but drains freely, has the right consistency to promote strong roots and seedlings are less likely to succumb to fungal diseases known as damping off.

Work out how many seeds to sow. How many lettuces, cabbages guard spring onions and so on will you and your family eat and when? For successive harvests sow enough seeds (plus a few more just in case) every two to three weeks for the number of plants you can manage to eat over two to three weeks. On the other hand, if you want to produce a bulk crop for preserving (gherkins or dwarf beans for example) plant the seeds for the number of plants you want (plus a few more as insurance) all at once.

For home gardeners keen to propagate seeds, alternatives to plastic pots include newspaper pots, toilet paper rolls and egg carton trays.

ALAMY STOCK/Stuff

For home gardeners keen to propagate seeds, alternatives to plastic pots include newspaper pots, toilet paper rolls and egg carton trays.

Do your research. Different seeds have specific requirements for germination – some need light, soaking in water, planting deep or on the soil surface or will only sprout when the soil reaches a particular temperature range. These details should be on the seed packet or consult the Kings Seeds catalogue.

Seedlings need consistent temperatures day and night. A windowsill may be warm when the sun shines but frigid on a frosty evening.

Watering needs to be consistent too. Keep the seed raising mix evenly moist but not suddenly. Lightly spray with a mister or water by sitting the punnets in a shallow container of water then allow to drain. Don’t leave punnets sitting in a puddle of water for long periods.

Get the light right. If seedlings don’t get enough sunshine they will become leggy and weak as they stretch towards the light.

Let the air in. Ventilation allows air movement around the growing seedlings which decreases the risk of fungal diseases taking hold.

Potting on means planting a seedling in a small pot into a bigger one.

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Potting on means planting a seedling in a small pot into a bigger one.

Pricking out, potting on & planting out

Pricking out means moving seedlings from trays into individual pots, potting on is planting a seedling in a small pot into a bigger one, while planting out involves transplanting your seedlings out into the garden.

Start pricking out when seedlings are big enough to handle. Work with a few seedlings at a time so they don’t dry out. Hold by the leaves so the roots are disturbed as little as possible. Remove a small clump of seedlings from the tray, gently tease the roots apart and plant individual seedlings into separate small pots or divided punnets.

Fill the new pots or punnets with potting mix. Make a hole with your finger, a chopstick or pencil then gently ease the roots into the hole and firm the mix around them. Water gently as above.

Divided punnets are suitable for fast-growing salad crops that are going to be transplanted into the garden within a few weeks. Individual pots suit larger plants like tomatoes and chillies, especially if they are going to be potted on into bigger containers while waiting for warmer conditions outdoors. Use potting mix when potting on as larger seedlings need more nutrients than seed raising mix can provide.

Potting on is also a useful strategy for those with very restricted growing space, for example a Vegepod, square foot garden or similar growing system. As soon as each plant is harvested it can be replaced by a potted-on transplant, so maximum use is made of the limited garden space.

Hardening off and transplanting

Acclimatising or preparing seedlings for life outdoors is called hardening off. Put seedlings outside in a sheltered place for a short time. For a week or two gradually increase the time they’re outside until they’re outside all day. Run your hand gently over the tops of the seedling leaves too. This simulates wind and encourages sturdier growth.

As long as the weather conditions are suitable, it is best to transplant seedlings into their final growing position while they are still small as they will establish more quickly than those that have become rootbound in the punnets. Once they’re planted out, they need less attention, and you’ve freed up space on your windowsill or wherever your seed trays are being coddled.

It doesn’t hurt to keep a few seedlings in reserve just in case and excess seedlings can be shared with neighbors, friends and family.

Once seedlings have been transplanted into the garden they’ll need protection from the weather, slugs, snails, birds, cats and dogs.

Read more:

Grow your own tomato plants from seed.

SALLY TAGG/NZ GARDENER/Stuff

Grow your own tomato plants from seed.

Raise tomatoes from seed sown in pots under cover

Growing your own tomatoes from seed is economical if you want to grow many different varieties, or if you’ve saved seed from last year’s fruit. They do, however, need a little mollycoddling.

Sow tomato seeds in seed trays or small individual pots filled with sterile seed-raising mix. Don’t sow too deep – a light (1-2mm) sprinkle of seed-raising over the top is sufficient. Ensure the mix is ​​moist, but not waterlogged, and cover with a plastic bag. This traps the humidity to speed up sprouting.

Place the trays or pots in a warm spot, such as inside a hot water cupboard.

As soon as you see signs of germination, remove the plastic bag and move the pots into a brightly lit location indoors, such as a sunny windowsill. They need as much natural light as possible, or they’ll grow tall and spindly (leggy). Once they are 3-5 cm tall, move them under a cloche or to a tunnel house for better light.

The seedlings will need repotting into larger pots of potting mix after a month. They should be ready to transplant from Labor Weekend onwards.

A large container of mixed lettuces, spinach and beetroot in a sunny spot by the kitchen door are handy for picking leaf by leaf for sandwiches, salads and wraps.

BARBARA/Stuff

A large container of mixed lettuces, spinach and beetroot in a sunny spot by the kitchen door are handy for picking leaf by leaf for sandwiches, salads and wraps.

Fill the hungry gap with microgreens and container-grown salads

In spring my culinary thoughts turn from soups to salads, but the garden can be rather bare this early in spring which means slim pickings when looking for leaves to eat. For greens in a hurry I grow microgreens on the windowsill and a box of lettuce and spinach by the kitchen door.

Peas as microgreens are delicious! Try ‘Tasty Tendrils’ from Kings Seeds. The bright green tendrils really taste like peas and they’re so easy to grow. Sow the seeds thickly into a punnet of seed raising mix, cover lightly with more mix and mist with water daily. Expect to start snipping in one to two weeks.

A container full of cut-and-come-again salad greens makes harvesting a breeze. Just pick a leaf or two off each plant – straight into the salad spinner and workday lunches are sorted. Good choices are spinach, loose-leaf lettuces, coriander, mesclun, rocketAsian greens, mizunamustard, radishes and beetroot.

Greens grown rapidly don’t get a chance to be bitter so it’s worth cosseting the container in a warm place where you can give it daily attention. Keep it evenly watered and liquid feed weekly with seaweed fertilizer or worm tea. Cover with a cloche for protection from birds, cats and the weather.

Salad greens grown this way can be much closer together than those in the garden. Picking leaves daily makes more room and if necessary, some seedlings can be thinned out.

Plant a new container in two to three weeks ready to harvest when the first one is finished.

Gardening by the moon

The fertile period continues until September 10. Sow leaf-crop seeds into well-worked soils; lettuces and peas do especially well. From September 11-14 leave off seed sowing. Weed and cultivate instead. On September 15 and 16 sow carrots and parsnips. Plant potatoes.

Gardening by the maramataka

Now is the move into kōanga (spring), the season to lift the kō. The relationship of the sun (te Rā) to his second wife (Hine-raumati, the summer maiden) is evolving at this time and all activities should lead to a successful cropping season in the upcoming summer. This is the planting season once temperatures warm up accordingly. We cannot plant into cold soil, so know your site and recognize the warm areas to start early crops. Kūmara beds can begin to be prepared now and similarly the clearing of land for late spring planting of other crops. We start this month with the full moon on the 10th, again a cold night, and Whiro (new moon) also on September 26. Seeds saved prior to winter now need to be warmed to encourage new sprouts. This includes taewa which should be brought out of cool storage and placed under trees for natural warming. Be aware of the solstice and influence of Tāwhiri-mātea around the 21st of the month. Dr. Nick Roskruge