Jobs to do in June

Sowing and planting

Vegetables

• Continue sowing salad crops, such as beetroot, lettuce, pak choi and radish. Leafy salad crops may do better when sown in partially shady sites since hot dry weather can lead to bitter tasting leaves.
• Sow French and runner beans, peas, squash, sweetcorn, and outdoor cucumbers directly into prepared beds outside.
• French beans are best sown in rows, 45cm (18in) apart, at 15-22cm (6-9in) spacing.
• Sweetcorn works best planted in blocks, at least 45cm (18in) spacing, with two seeds per hole. Any seeds sown earlier under cover can now be planted out into the same block pattern. Sow before mid June.
• Runner beans need well-prepared ground and suitable supports (often a frame or wigwam of bamboo canes tied together with twine) for the shoots to twine around and grow upwards.
• Courgettes, marrows and pumpkins can still be sown outdoors in early June in southern districts.
• Although most winter brassicas need to be sown earlier in the season, calabrese, turnips and kohl rabi can be sown now for an autumn crop.
• Start treating potatoes and tomatoes against blight.
• Celeriac and celery can be planted out early this month. A well-prepared site with lots of organic matter dug in is essential.
• Outdoor ridge cucumbers can be planted out early this month. They benefit from a site that has been enriched with lots of organic matter to help retain water.
• Plant vegetables sown indoors earlier in the season, including winter brassicas and sweet peppers. Peppers can only be planted out when all risk of frost has passed, and ideally beneath cloches.
• Gaps between winter brassica plants can be used for quick-maturing catch crops, perhaps radishes or gem lettuces.
• Plant out artichokes that were previously sown under cover. They can be grown as perennials (in which case they need 90cm spacing), or as biennials (45cm spacing is sufficient).

Fruit

• Transplant outdoor melons under cloches, pinching out the growing point.
• Move forced strawberries outdoors.

Pruning and training

Fruit

• Continue training fan-trained trees.
• Pull off suckers appearing around the base of fruit trees.
• Pinch prune figs.
• Thin pears, plums, peaches, nectarines and apricots. Apples should be thinned at the end of the month.
• Train in new shoots of blackberries and hybrid berries.
• Summer prune red and white currants and gooseberries.
• Shorten newly planted raspberry canes once new shoots are produced.
• Summer prune kiwifruit and indoor grapes.
• Thin out fruit of indoor grapevines if large dessert grapes are required.

Problems

Vegetables

• Keep an eye out for asparagus beetles and their larvae.
• Pinching out the top of broad beans once the lowest flowers have set will help prevent aphid attack.
• Look out for flea beetles on brassicas.
• Ward off carrot fly by covering plants with a fine woven plastic mesh like Enviromesh.
• Slugs pose a threat, especially to newly-planted seedlings and slug controls are necessary now.
• Pick yellowing leaves off brassicas promptly to prevent spread of grey mould and brassica downy mildew.
• Damping off of seedlings can be a problem both outside and in containers.
• Deal with red spider mite, whitefly, codling moth and plum moth and raspberry beetle.
• Net cherries against birds, keep protection in place for all soft fruit.
• Look out for shothole on tree fruit, especially stone fruit – a sign of possible disease infection.

General care

Fruit

• Change the feed for pot-grown fruit to a high potassium liquid one.
• Peg down strawberry runners and remove cloches from outdoor strawberries once cropped.
• Water blueberries, cranberries and lingonberries regularly with rainwater. Use tapwater when butts run dry.
• Water and feed indoor melons daily once they are established and plant into growing-bags in a heated greenhouse.
• Avoid using insecticides on crops when they are in flower.
• Make sure fruit isn’t drought stressed, especially in containers, against a wall or newly planted.

Vegetables

• Regularly feed ridge cucumbers with a liquid tomato feed, following the instructions given.
• Peas need staking with pea sticks, netting or pruned garden twigs.
• Continue to earth up maincrop potatoes.
• Do not harvest asparagus spears from crowns less than two years old.
• Hoe between rows on hot days to make sure weeds dry up and die without re-rooting or they will compete for moisture and nutrients. Weedkiller might kill or damage your crops as well as the weeds.
• Water tomatoes and peppers regularly to prevent blossom end rot – a symptom of calcium deficiency due to erratic water supply.