Estimated Crop Yields

EXPECTED YIELDS

There can be very marked differences between yields of different plantings of a vegetable crop, depending on the cultivar selected, and on the environmental conditions prevailing during the growth of the crop. Even larger differences in yield between crops can be ascribed to the cultural practices applied, and to the relative expertise of the individual growers. Certain farmers consistently achieve good yields of good quality, while others produce poor crops. This difference in the ability of growers is of particular importance with horticultural crops, which are grown intensively.

Whether the causes of yield differences are environmental or managerial, a grower inexperienced in a particular vegetable crop needs to have some indication of potential yield as an aid when making decisions about growing the crop.

Expected yields from commercial plantings of some vegetable crops can be listed under three headings:

The conservative yield

The "conservative" yield is that obtained from a relatively poor crop, and is frequently not economical to produce, unless particularly high prices are realised.

The likely yield

The "likely" yield is that achieved from the majority of plantings by the average grower.

The target yield

The "target" figures are those that a good grower could realistically achieve in practice. These are not considered to be the potential yields of the prospective crops. For example, the target figure for dwarf green beans is given as 10 to 15 tons per hectare. Yields of over 20 tons per hectare have been achieved by some growers, even from large plantings, and certain trial plots have yielded the equivalent of about 30 tons per hectare. Similarly, carrots could yield in excess of 70 tons per hectare, cabbage over 110 tons per hectare and tomatoes more than 100 tons per hectare, from specific commercial plantings. However, such yields are exceptional. Yields that a commercial grower may expect from the main vegetable crops grown, divided according to the above categories, are suggested in the following table.

Table 8.

Commercial yields of vegetable crops.

Crop

Yield in tons per hectare

 

 

Conservative

Likely

 

Target

 

 

Artichoke, globe

3

5

 

7

- 8

 

 

 

 

 

 

Asparagus

1,5

2,5

 

         4

 

 

 

 

 

 

 

Bean, broad

3 - 4

5 - 6

 

7

- 8

 

 

 

 

 

 

Bean, dwarf, green

5

7 - 8

 

10

- 15

 

 

 

 

 

Bean, lima

5

7

 

10

 

 

 

 

 

 

Bean, runner, green

7

10

 

15

- 20

 

 

 

 

 

 

 

Crop

 

Yield in tons per hectare

 

 

Conservative

Likely

 

Target

 

 

Beetroot

14

18

 

25

 

 

 

 

 

 

 

Broccoli

 

5

 

8

 

12

 

 

 

 

 

 

Brussels sprouts

 

7

10

 

15

 

 

 

 

 

 

 

Butternut

12

15

- 18

 

25

- 30

 

 

 

 

 

 

Cabbage

30

50

 

80

- 90

 

 

 

 

 

Carrot, large

20

30

 

40

 

 

 

 

 

Carrot, baby

10

15

 

20

 

 

 

 

 

 

 

 

Cauliflower

7

- 8

10

- 12

 

15

- 20

 

 

 

 

 

 

 

Celery

15

- 20

25

- 30

 

40

 

 

 

 

 

 

Chilli, green

 

7

10

 

15

 

 

 

 

 

 

Chilli, dry

1,5

2,5

 

 

4

 

 

 

 

 

 

 

Cucumber

12

15

- 18

 

25

- 30

 

 

 

 

 

 

Egg-fruit

12

- 15

20

 

25

 

 

 

 

 

 

Garlic

 

6

10

 

15

 

 

 

 

 

 

Gem squash

12

15

- 18

 

25 -30

 

 

 

 

 

 

 

Hubbard squash

12

- 15

18

- 20

 

30

 

 

 

 

 

 

 

 

Lettuce

12

- 15

20

- 25

 

30

- 40

 

 

 

 

 

 

 

Marrow, bush, large

12

15

- 18

 

25

- 30

 

 

 

 

 

 

Marrow, baby

7

- 8

12

 

15

 

 

 

 

 

 

Melon, musk

12

15

- 18

 

25

 

 

 

 

 

 

Melon, sweet

12

15

- 18

 

25

 

 

 

 

 

 

Melon, water

12

- 15

20

 

30

 

 

 

 

 

 

 

Onion, large

15

- 20

25

- 30

 

40

 

 

 

 

 

 

Paprika, dry

1,5

2,5

 

4

- 5

 

 

 

 

 

 

 

 

Parsley

 

2

 

3

 

 

4

 

 

 

 

 

 

 

 

Parsnip

10

- 12

15

- 18

 

20

- 25

 

 

 

 

 

 

 

Pea, green, in pods

 

4

 

6

 

8 - 10

 

 

 

 

 

 

 

 

Pea, edible podded

2

- 3

4

- 5

 

6

- 7

 

 

 

 

 

Pepper, sweet, bell

20

30

 

40

 

 

 

 

 

 

 

 

 

Crop

 

Yield in tons per hectare

 

Conservative

Likely

 

Target

 

 

Potato, dryland or hot areas

10

17

 

28

 

 

 

 

 

Potato, irrigation

17

28

 

45

 

 

 

 

 

 

Pumpkin, boer

12

- 15

18 - 20

 

30

 

 

 

 

 

 

Spinach, true

7

- 8

10 - 12

 

15 - 20

 

 

 

 

 

 

Sweet-corn

7

- 8

10

 

15

 

 

 

 

 

 

Sweet potato

15

- 20

25 - 30

 

40

 

 

 

 

 

Swiss chard

20

30

 

40

 

 

 

 

 

Tomato

30

45 - 50

 

60 - 80