How To Grow Cucumbers / RHS Gardening

Plant indoor-sown or newly bought cucumber plants into their final growing site in late spring or early summer, depending on where they will be growing:

• Greenhouse cucumbers – from late May, plant into a greenhouse border or large pots once the temperature inside is consistently above 12°C (53°F). Or, if you have a heated greenhouse, you can plant as early as late March.
• Outdoor cucumbers – harden off seedlings A seedling is a young plant grown from seed. carefully, to acclimatise them to outdoor conditions, before planting out from early June onwards, once your local temperatures are reliably above 12°C (53°F).

Planting cucumbers is very straightforward – water them well beforehand and try not to disturb the rootball The roots and accompanying soil when a plant is removed from a container or lifted from the ground. , so they settle in quickly without a check in growth:

• To plant in a container – choose a pot that is at least 30cm (1ft) wide and deep, and fill with peat-free multi-purpose compost Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own. . Position one plant in the centre, firm it in gently and water generously, then add suitable supports (see below). Alternatively, plant two cucumbers in a standard-sized growing bag.
• To plant in the ground – plant one cucumber plant into the centre of each prepared growing site (see above), spacing them 30cm (1ft) apart. Firm in gently then water well. Add supports (see below) if you want to train the plants vertically.

Related RHS Guides

Putting up supports

Cucumbers are climbing or scrambling plants that can either be grown up supports or allowed to trail on the ground. Growing them vertically means they take up very little ground space, which is useful in small gardens as well as small greenhouses. It also keeps the fruits clean and away from slugs.Put the supports in place at planting time so their tendrils have something to cling to. The stems need tying in initially, and may need help later if they lose their way or come loose, especially outdoors and when carrying fruit.

The type of support you need depends on where you are growing your plants:

• Greenhouse cucumbers – insert a tall, sturdy bamboo cane A cane is a slender, straight, length of woody plant material, usually bamboo. Canes are primarily used as plant supports. The fruiting stems of blackberries, raspberries and hybrid berries (such as loganberries and tayberries) are also known as canes, so these crops are often referred to as cane fruit. that reaches up to the greenhouse roof, or attach a vertical wire or string from the roof, secured at ground level. Horizontal supports may also be required for side-shoots
• Outdoor cucumbers – build a wigwam or other structure from tall bamboo canes, or use stout netting supported vertically on upright stakes. Cucumbers will also climb up trellis or wires attached to a wall or fence.

If you plan to leave your cucumber plants to trail over the ground, it can be helpful to lay plastic-free weed-suppressing membrane over the soil after planting. This helps to keep fruit clean and prevent rotting, and is much easier than protecting each fruit individually when growing small-fruited varieties that crop heavily.

Related RHS Guides