Planting Peas and Potatoes on St Patrick’s Day

“Planting peas and potatoes on St Patricks Day?” I hear you say, “Shouldn’t that be planting clover or shamrock?”

A good question! Clover does make an alternative ground cover planting to a traditional turf lawn. And the Shamrock is the main plant associated with St Patrick, who’s saint’s day falls on March 17th. However, March 17th is one of those dates in the gardener’s year when it is ‘time’ to sow seeds of particular plants. In this case, peas and potatoes. But first, a little bit of social and garden history on the importance of these vegetables in Ireland.

Planting Peas and Potatoes

The tradition of planting peas and potatoes on St Patrick’s Day is popular in both the USA and the UK. But it is not purely down to the Saint’s passion for these vegetables! Indeed, it would have been difficult for St Patrick to enjoy roast potatoes for his dinner in the 7th century. This vegetable is native to the Americas but wasn’t introduced into Ireland until the 1600s. Peas, however, were known and grown in the Middle Ages, being a staple ingredient of the peasant dish of pottage.

Of course, the potato became another staple of the Irish diet, with tragic consequences in the Potato Famine of 1845-51. By this point, the Irish peasantry depended on the potato; it was their main food source. No wonder it has been called The Great Hunger.

Potato Blight and Famine

The Great Hunger crop failures were caused by a late season blight, Phytophthora infestans, which destroys the edible tubers. Ironically also introduced from America, this blight was able to decimate the potato harvest as the Irish were dependant on only two varieties of potato. This lack of genetic variety in a staple crop is critical as it makes a population more vulnerable to poor harvests. A fact that is as true today as then.

Combined with the wet summers and wet soil that provided an active breeding ground for this water borne pathogen, the outcome was devastating. About 1.5 million people died as a result of the famine, directly through starvation, or indirectly through disease.

This same blight also hit the potato crop in Western Scotland, although the Highland Potato Famine gets less press. The famine-struck population, like that in Ireland, took to emigration as a means of escape.

These days, there are blight resistant strains of potato, but late blight is still a threat. Whilst fungicides are used to combat the effects, the blight is becoming resistant to them. Genetically modified potatoes that basically turn late blight’s genes into its own enemy are being developed. However, climate change is now creating a problem with early blight, Alternaria alternata. A change in farming practices, for example, a wider usage of intercropping, rather than a monoculture, may prove a resilient approach for many producers.

There are sound gardening reasons why we shouldn’t cultivate our vegetables in a monoculture. And a lack of space in gardens and allotments may encourage us to find flexible ways of growing vegetables. Look through the Plews blog categories for ‘Soil’ and ‘Edible Gardens’ for more on this (some blog links below). Or ask about our Gardening Classes where your garden is your classroom.

Why plant peas on St Patrick’s Day?

So why is mid-March a good time to be planting peas and potatoes in our gardens and allotments? The answer is quite simple. It’s when the soil and the weather are optimum for planting and sowing.
You’re right, its not quite that simple in reality, but with a modicum of flexibility we can keep it fairly simple. Given the vagaries of the British climate, gardeners are well advised to approach planting peas in a range of ways.

Try these: –

Peas can be sown in mid – late winter in cool greenhouses, polytunnels and cold frames.
To encourage germination with an early outdoor planting, its an idea to cover the soil with fleece beforehand. They like a soil temperature of at least 7 Celsius.
Another option which I’ve found works is to soak the pea seeds in warm water before planting.
Pre-germinate the pea seeds on warm moist kitchen towel. This does give you the fiddly task of planting peas that have begun to sprout without damaging those tiny roots and shoots.

Oh, and perversely, peas relish a cool period to encourage germination: late sowings in the summer never have as luxuriant a growth.

Now if all that sounds fiddly, remember these seed sowing methods are spread over a few months. With only small quantities of peas involved at any one time, it doesn’t take long. No more so than successional sowing; which you’ll need to do so there’s not a glut of peas.

Planting Potatoes and Reducing Blight

How can we reduce the likelihood of losing our own potato crops to late blight? The two easiest ways are: –

be sure to buy certified seed potatoes
grow early potatoes which are lifted before late blight is prevalent

Of course, that only resolves one issue, there are other pests and diseases that affect potatoes. For example, eelworms and slugs. But don’t let that put you off planting potatoes on St Patrick’s Day or indeed a fortnight later! Read Growing Potatoes (below) for tips on cultivating this useful vegetable – even when you don’t have an allotment or large garden.

Planting Peas and Potatoes on St Patrick’s Day – a few Tips and Thoughts

Both peas and potatoes are sold as ‘early’, ‘second early’ and ‘maincrop’ varieties. What this refers to is the how long they take to germinate and mature to cropping readiness.

Peas, Pisum sativum

earlies take 11-12 weeks
second earlies 12-13 weeks
maincrop 13-14 weeks
dwarfing varieties tend to be earlies
with a few exceptions, all types can be planted at any appropriate time

Types of Pea

shelling or standard peas; wrinkled peas are sweeter than smooth but less hardy
shelling, petit pois; small very sweet peas
mangetout; flat podded are eaten whole, although can be left to mature and peas removed to eat
mangetout; round pods, sugar snap type
semi-leafless pea shoots (tendrils) can be added to salads

Potatoes, Solanum tuberosum

earlies take 13-15 weeks
second earlies 15-17 weeks
maincrop 18-22 weeks
chitting potatoes reduces the time in the ground
heaviest harvests are from maincrop potatoes

As for me, I’m planning on getting my chitted blue potatoes into the soil this weekend. Normally I’d be sowing peas outside too, but I’m behind myself, so I’m going to sow my peas in modules instead. That way they’ll easily transplant when I’ve prepared the ground for them. Peas don’t like having their roots disturbed.

I’ll also be sowing seeds of Coriander and Calendula as they’re good companion plants. And checking my late summer cuttings of culinary Thyme which I love to use around vegetables, both as a companion plant and also for the convenience of picking herbs to go with the vegetables in cooking!

For more on plot to pot gardens and edible garden designs, why not drop us an email?