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Selecting for the Porto range |
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 There are three sizes of Porto. Each Porto is suitable for a certain number of stems. The number of stems that actually fit in the Porto depends on a number of factors:
- Diameter of the stems. Stem diameters differ for different flowers.
- Roughness of the stems. This means the bulges (carnations) and thorns (roses)
- Leaves on the stems. Stems with leaves at the stem ends are thicker.
- Rigidity of the stems. Weak stems are more sensitive to the lips in the opening of the Porto.
In general the number of stems depends on the diameter of the bunch at the place the stems end. If the diameter of the bunch is 70% of the diameter of the opening in the Porto (plus/minus 20%) the grip fingers will work optimally – and the stems will be optimally supplied with water in the Porto.
| Porto |
Diameter of the opening |
70% of the opening, diameter |
70% - 20% of the opening, diameter |
70% + 20% of the opening, diameter |
| Porto 10 |
4.25 cm |
3.6 cm |
3 cm |
4 cm |
| Porto 20 |
6 cm |
5 cm |
4.25 cm |
5.7 cm |
| Porto 50 |
9.25 cm |
7 cm |
6.5 cm |
8.8 cm |
And so, the number stems that actually fit in the must be determined by experimentation.
Water Capacity
All Portos contain a certain quantity of water which is enough for 2 days at 30°Celsius. This is tested with large-bloomed Grand Prix roses (length 70 cm) Grand Prix roses are known to be “big drinkers” – and that’s why this variety was selected for tests. Under test conditions these roses drink around 4 ml per stem per day.
| Porto |
Amount of stems |
Days |
Water-use per day |
Total |
| Porto 10 |
10 |
2 |
4 ml |
80 ml |
| Porto 20 |
20 |
2 |
4 ml |
160 ml |
| Porto 50 |
50 |
2 |
4 ml |
400 ml |
Daily water requirements per stem depend on the type of flowers. In general we advise that thin stemmed flowers need less water. The fact that the stems are thinner means a higher number of stems per Porto. The assumption here is that the quantity of water in the Porto will still be enough for 2 days at 30 °Celsius.
In practice it’s very rare indeed that flowers spend 2 full days being transported in the Porto at 30° Celsius. So, in general the duration of transport can be longer. The less warm it is - the less water will be sufficient for the stems in the Porto. However, it should be noted here that the tests are carried out on slip-covered flowers in a closed box – which means limited evaporation. If the Portos with flowers are transported in open packaging with no covering this will have an impact on the duration of transport (it will be shorter).
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