SOW & GROW

Jo McCarroll suggests jobs to do in the edible garden.

June is here, can you even believe it?

It’s getting pretty cold out there for planting and sowing: you can still sow broad beans and peas direct (unless your soil is absolutely sodden or frozen) and plant elephant garlic, shallots and jerusalem artichokes. If you are in a region that gets a properly cold winter, you can plant garlic from the silverskin, porcelain, rocambole, glazed purple stripe, standard purple stripe or marbled purple stripe groups early this month. You can start lettuces, main crop onions, spinach and silverbeet in trays this month too; and plant seedlings of lettuces, silverbeet (including perpetual spinach), spinach and brassicas. If you have a small garden, look for the seedling combo of mini brassicas from Zealandia: it contains the broccoli ‘Green Midget’, the cabbage ‘Cannonball’ and the cauliflower ‘Mini White’. These are mini varieties and early maturing so you should have eaten them before white butterflies are back on the wing. I was talking to Paul Wylaars from Zealandia the other day and he said these brassicas could even be grown in pots, although you need a big pot (ideally 40 or 50L, I reckon) for each one.

How frost works in the vegetable garden

Frosts are not all bad, they actually make certain edible crops taste sweeter. Root crops like carrots, turnips, parsnips, swedes and beets, and brassicas such as brussels sprouts, broccoli and kale will also sweeten up. These plants take in energy (from the sun and from the soil) and covert it into starch, which is how they mainly store energy. But when it starts to get colder they respond by, effectively, harding themselves off: the walls of the cells inside the plants get thicker and the cells themselves smaller and the sugar-to-starch ratio goes up. That’s to stop frost damaging these plants – the sugar acts like a natural antifreeze, stopping the water in the plant cells from freezing because water swells when it freezes which ruptures the cell walls (exactly what happens when you freeze veges and then thaw them, and they turn mushy); plus the plants can use the energy in the sugar to stay warm. I think I understand the science but I don’t get a frost in my Auckland garden, so I don’t know how much sweeter things taste? If you are growing inland or down south, let me know!

What to prune in June

People tie themselves in knots about the timing of pruning but don’t get stressed, just remember the basic rule: when it is cold you are pruning for shape and when it’s warmer you are pruning to control size and reduce vigour. In your home orchard, you want to prune apple, pears, cherries, feijoas, figs, nuts and olives in winter and do any shaping that citrus requires, although they don’t need a lot of pruning really, just enough to keep them at a harvestable size and open up the centre.

Winter is the right time to undertake a renovation of old overgrown trees, especially deciduous trees as with the leaves off you can better see the branches and assess the form. Remove about 20% of the growth of an old tree at one time, no more. I have tried to rush the renovation of an old plum tree and just hacked it brutally back and the tree responded with a huge burst of growth and is now more thicket-like than ever. Whatever you are pruning, first remove the three Ds – any growth that is dead, diseased or damaged – then any branches that cross, grow inward or otherwise interfere with your intended form. Then shorten any branches that are longer than you want.

If you have or will purchase bare root fruit trees this winter, then plant them as soon as you can after you get them home and prune them at the same time, shaping them into a central leader/modified central leader (for pipfruit) or a vase shape (for stonefruit). Bare-rooted trees can take quite a hard prune when you plant them, you can cut them back by about a third. It seems a bit mean, I know – you feel like you should let them get established before you start chopping branches off. But it means that from day one that tree is putting its energy into developing a strong root system and branches which you plan to keep.

Prune on a dry day, and wait until the forecast looks like it will stay dry for another few days. Wet conditions increase the risk of post-pruning bacterial or fungal problems. Think of the pruning cuts as wounds to the tree; and like wounds, they can get infected.

It’s also possible to prune blackberries, boysenberries, blueberries, red- and blackcurrants, autumn- and summer-fruiting raspberries, grapes, gooseberries and loganberries in winter. You prune them all differently and to a different degree; do your research before you prune anything to make sure you don’t cut off all of next year’s fruit-bearing stems or canes.