There are many ways that you can harvest, using both tools and hands. I explain the methods, and how they influence subsequent growth.
This lesson uses certain vegetables as examples, in order to illustrate each method. The next lesson has more harvesting details for other vegetables, especially in terms of best timings.
The many types of vegetables need different picking skills, to achieve regular harvests of high quality and preferred flavour. These skills will help you to grow more from less space, save time and suffer less pest damage.
Harvesting methods
The more you harvest, the quicker and easier it becomes. Practise picking leaves and pulling roots, and learn the best way to use a knife.
Picking leaf by leaf
For harvesting leaves, it’s best to avoid the common method ‘cut and come again’. Any cuts of small central leaves slow down growth for the next harvest, because it’s those small leaves that power new growth, with the most photosynthesis per leaf area.
A no-knife harvest, on the other hand, results in optimum plant health and continued growth. Pick leaves from the bottom up, the older leaves first, and always leave the smallest and youngest heart leaves.
- Picking outer leaves gives a steady supply of roughly the same amount, each time you pick.
- Small heart leaves do more photosynthesis per area than larger leaves, so removing many larger leaves does not massively reduce growth.
- Lower leaves of leaf lettuce are less sweet than heart leaves, but contain beneficial phytochemicals, such as polyphenols and quercetins.
- You enjoy extra weeks of harvest from the same plants, so you need less time over a season for clearing and replanting.
- Beds look fuller and more attractive with plants always growing strongly, and with an ebb and flow of plant size as regrowth follows each pick.
To pick lettuce and endive leaves, position your thumb on the stalk, close to the plant stem, and then push down while also rotating the leaf. Aim to remove the whole stalk of every leaf, so that the plant stem stays clean with smooth edges.
This reduces hiding places for pests and makes the next pick easier.
To pick the larger leaves of salad rocket and mustards, use your thumbnail (or a small knife or scissors) to cut through the leaf stalk, close to the plant’s main stem.
How many leaves you pick depends on two things: how soon you want another harvest, and the time of year. We pick more leaves from each plant in summer because they grow so fast, and also during the pick before Christmas so that we can then have an annual holiday.
Cutting across the top – leaf harvests
Cutting is mainly viable when there are tens, or even hundreds of small leaves, as opposed to fewer large ones. This is the case when you sow seeds thickly, and for certain vegetables.
In one hand, gather the leaves of the whole plant you are cutting. Then, with a sharp knife, slice through the leaves just below where you are holding them, as in the photo below.
- You should always see tiny heart leaves below the level of your cut. If you see only stems, the cut was too low and the plant probably won’t regrow.
- Growth is slower after cutting across the top compared to picking outer leaves, because the baby centre leaves have lost some leaf area.
With wild rocket and frizzy endive, you might first pick a few outer leaves by hand when plants are small, perhaps twice at a weekly interval. You can then switch to regular cutting over three to four months.
Older plants, of wild rocket and frizzy endive, change character and grow many smaller leaves instead of fewer large ones. It’s still feasible to pick around the centre, but with these plants it’s often quicker to cut across the top, and not too deep.
Cutting other vegetables
The main use of a knife is for cutting hearts such as cabbage, also large heads of broccoli and celery plus leeks, as explained below.
Sideshoots of broccoli can either be cut with a knife or snapped off using your hands. An advantage of using your hands is that when bending a stem to snap it, you can feel where it starts to become tough and fibrous as it does not snap. You can then move your finger and thumb upwards to snap where it’s tender.
Pull or push, twist or cut – stems and roots
STEM VEGETABLES
For celery and leeks, use a combination of cutting and pulling.
The best method for harvesting leeks depends on how deep you planted them. With multisown clumps, and in no dig soil, a trowel is usually your best tool for cutting through roots just below each clump, while pulling gently upwards at the same time. Or you can cut the roots of just one leek in a clump, though avoiding damaging other leek roots in the same clump takes practice.
I advise cutting leek roots when harvesting, rather than simply pulling the plants, because their root system is so large and strong. Any pull without cutting roots will result in significant soil disturbance. If this does happen, push, or even tread soil back down after harvest to make it firm again.
You can either cut celery at the base of any stem, to harvest all of it, or cut off individual leaves – there are celery varieties bred for leaf harvests and they do not make a tight stem.
After you have harvested a celery stem, there is some edible regrowth from the roots. If you don’t want that, cut just below soil level, or use a trowel to cut through the roots. Or you can pull gently, and twist the whole plant while also cutting roots. This snaps the base away from most of the small roots, which then remain in the soil.
ROOT VEGETABLES
These are mostly easier to harvest than you might imagine, especially with no dig because the surface is soft as well as being firm. This may sound contradictory, but try it and see!
Another factor in ease of harvest is that many root vegetables sit on the surface.
Potatoes
I am often asked, ‘How, with no dig, do you dig out your potatoes?’ This is a question that demonstrates how it’s good to think afresh and ask questions differently.
The soft surface of no dig beds, rich in organic matter, means that you don’t need to use a fork or spade for harvesting potatoes. Furthermore you do not need to plantthem deeply (see Lesson 8).
Place your hands firmly around all the stems of any potato plant you want to harvest, and then ease them upwards gently. Half to three-quarters of the potatoes will come up with the stems, and then you can feel in the ground for the remaining ones.
In undisturbed, no dig soil, potato tubers (unlike plant roots) can’t move their way down to any depth, because the soil there is too firm.
- An exception to this is sandy soil, which, even with no dig, is quite loose. Tubers can therefore develop quite deeply and you may need to use a fork or spade to find them all.
Other root vegetables
For root vegetables that grow below ground, such as carrots and parsnips, harvest by pulling them gently upwards, with your hands clasped around all stems emerging close to ground level. Parsnips, however, may require a spade to lever them up, while disturbing the soil as little as you can.
With root vegetables that are close to the surface, such as beetroot, twist them out to cause least disturbance to the soil. You can selectively harvest any larger roots this way, even from multisown clumps.
For celeriac, use a knife or even a sharp spade to cut under the bulbs, leaving their mass of fairly small roots to decay in the soil over winter.
FRUITING VEGETABLES
When harvesting cucumbers, melons, squash, and even courgette, cut through the stalk with the aim of leaving it attached to the vegetable.
For tomatoes, it’s a little different – put your thumb on the green calyx (flower-shaped leaf), and push downwards to detach it from the truss. Keeping the calyx attached allows tomatoes to be stored for longer, because there is no split or rip of the skin.
For peas, and both French and runner beans, a pull can work best, sometimes while holding the main plant stem.
For broad beans, harvest is easiest when you push downwards on the stalk of pods, close to the plant stems. It’s a push, not a pull, so that each pod detaches cleanly and without damage.
Sweetcorn picking is also done with a downward push – this snaps pods cleanly from the plant stems.
When you cut, pick or pull – do this!
A really useful habit to acquire when harvesting anything in the garden is to have two receptacles with you. One is whatever you put your harvested produce into; the other is a bucket, or any container, for diseased or damaged leaves, fruits and roots, and also for weeds and any pests you may find. We call it the compost bucket, since we empty all contents on the heap.
This means that you are doing two jobs at once, with only a little extra effort since you are there anyway. Your harvested plants become tidy, look good and harbour fewer pests. The reason for the latter is that pests, slugs in particular, are more attracted to older and decaying leaves.
Furthermore, because you acquire this mentality of cleaning and tidying as well as harvesting, your garden keeps progressing on an upward curve to become more productive and beautiful.
Harvest amounts
Spacing affects harvest quantity, together with the type of vegetable. For example, one might class cauliflower a luxury vegetable because the plants need a fair amount of space for one harvest. They do look and taste amazing though.
A more efficient use of space and time is to grow Brussels sprouts. Their total harvest is not huge for a plant needing at least half a season to grow, but this is mitigated by a long period of regular harvests, quite the opposite of cauliflowers. Another plus point is that sprouts are dense and full of flavour. If you haven’t tasted homegrown Brussels, I urge you to grow them; in maritime climates they are a repeating delicacy through winter.
Leaf vegetables, compared to those for fruits and roots, give the most weight of harvest, per plant and per area, because their amount is more water than dry matter. At the other end of this spectrum are winter squash, dry beans and garlic, whose weight of harvest per cropped area is low, but with a high food value per weight because they are so dense.
Plants in containers yield less than plants in soil because of their restricted root run, unless you feed and water continually. Tomato harvests from containers can be high when plants are well fed, watered, and grown in warmth. You can also harvest a decent amount of salad leaves and other leaf vegetables from just one container.
Leaves
Leaves for salads are the highest yielding and, in economic terms, most valuable plants per time and space when picked repeatedly and regularly.
Brassica salads – rockets, mustards and mizuna – give steady and high volumes of harvest in autumn, and in winter under cover.
Lettuce gives heavier harvests than almost any other vegetable, although spinach and chard come close at certain times of the year. Kale sown in mid-spring gives large amounts of fine leaves weekly, for several months until late autumn. Plants may survive winter but harvests are then much smaller.
In the Small Garden, I record lettuce harvests of over 6 kg / 13 lb, from areas of just 1.5 m2 / 16 ft2, during the ten- to twelve-week period of late spring to summer harvest. This is from using the outer-leaf picking method, which enables plants to live a long time.
Stems
Stem vegetables can give decent amounts to eat.
Every year, in my Three-Strip Trial, I grow potatoes for three months and then leeks for three months, in the same bed. The leek harvest, of trimmed stems with a little green leaf, averages 29 kg / 64 lb through every autumn. Leeks are highly worthwhile because you can harvest them as needed. Plus you have the option to use their greens in soups and stews, which increases the harvest total – my harvest weight figures include a third to half of the green leaves.
Celery grows in about half a season, and gives highly nutritious harvests. One trimmed head of celery here weighs around 400 g / 0.9 lb, spaced at 30 cm / 12 in. This equates to 9 kg / 86 lb of celery from an area equivalent to one of thebeds in my Three-Strip Trial. The celery harvest takes as little as two months in the ground, so it’s worth finding space for.
Roots
Root harvests do not repeat once you have pulled a plant to eat or sell. This limits the harvest if you remove all of the plants at one time, whereas selective thinning increases harvests and the harvest period.
The best yields come from beetroot, carrot, Jerusalem artichoke, parsnip and potato – they all provide a lot of food per area. Even celeriac can be highly productive, but you need to get everything right for that.
Conversely, you will not enjoy large harvests from Chinese artichoke, skirret, salsify and scorzonera. This is probably the reason they are not grown much.
