Anna Pavord: 'Plant up a new trough with delicious, successional spinach'

The demise of an old barrel has given our horticultural expert an idea...

Spinach can been sown every three weeks, from March to August (Getty Images)

The tulip 'Couleur Cardinal' is coming on very well in the wooden half barrel to the left of the greenhouse door. It's one of my favourite tulips. But although I love it, I am impatient for it to be over.

The problem is the barrel. A couple of the boards have rotted and snapped at the top, so the compost leaks out through the gap. I'm longing now to get rid of it because I see that what I ought to have in that space is a galvanised trough to match the one that stands on the other side of the greenhouse entrance. That one catches rainwater from the roof and provides pretty much all the water I need in the greenhouse.

The water trough is 88cm long x 46cm wide x 40cm deep. It came from our local agricultural supplier and cost £63.36. There's the same amount of space to the left of the greenhouse door as there is to the right, so a second trough will fit there perfectly. I'll use it exclusively for veg – spinach and salad crops – and I'll get holes punched in the bottom for drainage.

Even with holes at the bottom, there'll still have to be a layer of drainage material. On top of that, our own compost, which I can use to fill most of the tank, with the top couple of inches finished off with sterile bought-in compost. I can sow direct into that. Spinach is a crop you can sow every three weeks from March all the way through to August. I've lost the chance of an early crop, but as soon as those tulip petals drop, I'll be in there, shifting the furniture.

I'm thinking that I could sow one half of the trough at a time, which would make it easier to keep the succession going. But will half a trough provide enough spinach to make a meal from one cutting? I don't think the perpetual stuff has as good a flavour, so I'll stick to what I think of as 'proper' spinach.

I've tried both 'Apollo' (Thompson & Morgan, £2.49 for 500 seeds) and 'Fiorano' (Mr Fothergill, £2.09 for 300 seeds). Both grew fast, did not get mildew and tasted terrific, both raw as baby leaves in salad, and cooked, when allowed to get slightly bigger.

Spinach has two useful attributes for a gardener. It will grow in light shade, provided the ground is moist, and it grows fast. This means that, in open ground, you can sow a succession of spinach 'catch crops' between rows of slower maturing vegetables. I won't be doing that, but will certainly benefit from the speediness of the crop.

True spinach is an annual, which means that its one aim is to set seed and perpetuate itself. In hot, dry conditions, this works against the spinach fancier. Instead of pausing to produce a feast of handsome, arrow-shaped leaves, the plant races on up to maturity leaving only an unusable crop of creamish-green seed. In a container there is more danger of the compost drying out. But the trough is deep and relatively large. There will be a water supply right next to it. I'll have no excuse for not giving the spinach crop all the drink it could want.

Most of the generally available varieties are now bred with good resistance to mildew. Bolting has as much to do with summer heat as anything else. This is why, although you can sow from March to August, you generally get the best results from seed sown towards the beginning and the end of the sowing period.

If you are looking for crops of spinach during July and August, then they'll probably do best in some shade. A row of runner beans will offer protection at least for some of the day. So will a stand of sweetcorn. In the trough, I can't arrange that, but it'll be facing west. The spinach plants will at least start their days in shade. Galvanised metal doesn't provide the insulation offered by wood and heats up in the sun. But I think the size of the trough will help to keep the compost at a fairly even temperature. In a smaller container, this would be more of an issue.

Little and often will be the way with seed, and if I sow carefully, the plants shouldn't need thinning. Since spinach, like other leafy crops, is a great gobbler of nitrogen, the compost can scarcely be too rich for it. As a crop in open ground, it follows on well after peas and beans, which leave the soil better equipped with nitrogen than they found it. I'll have to add some liquid feed when I water. Depending on the weather, I'll probably get in two sowings of spinach between late April and May and another one in August. In between those times I'll grow cut-and-come-again salads. Sorted. I hope...

WEEKEND WORK

WHAT TO DO

* Indoor plants will now begin to need more food and drink. Remember, however, that far more fatalities are caused by over-watering rather than under-watering.

* New growth is well advanced on autumn perennials such as michaelmas daisy and rudbeckia. Splitting and resetting congested clumps increases their flower power. It is a job that can be done in autumn or spring.

* Continue to sow annuals. I am about to sow Gazania 'Tiger Stripes Mixed' (Thompson & Morgan, £3.69). Given a half-decent summer, gazanias are handsome additions to the garden.

WHAT TO SEE

* The 17th European Orchid Show and Conference opens in London next week with a preview evening on Wednesday (6.30-9pm, admission £18). There will be ravishing displays from professional growers, orchid societies and botanic gardens, alongside a series of lectures by some of the greatest experts in the world. The show continues until 12 April (open daily 10am-5pm, admission £11) at the RHS Halls, Vincent Square, London SW1. Get more information at eoclondon2015.org.uk