WEEK 1 WEEK 2 WEEK 3 WEEK 4 WEEK 5 WEEK 6
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Crop growth has increased this week in response to a steady rise in temperatures from 19oC at the beginning of the week, to 26oC at the end; this is substantially above the historical average temperature of 18oC for mid-May. Nighttime temperatures have ranged from 7oC to 12oC and are ‘in and around’ the historical average of 9oC. No rainfall occurred during the week, extending and intensifying the period of dry weather which began at the beginning of March.
The plants are now sufficiently well-established not to require any supplementary watering and daily timed irrigation is adequate, providing approximately 4 litres per planter per day. For us, this is operated by a Rainbird controller which has an adjustment for rainfall.
All three radishes in Planter 1 are continuing to be harvested. However, radish ‘Cherry Belle’ and ‘Polenza’ are showing signs of deterioration with a number of larger radishes having split and or become slightly woody. The tops of larger bulbs have become exposed at the soil surface. It is clear that these two varieties have been affected by the exceptionally high temperatures experienced. Radish ‘White Icicle’ in contrast, is proving far more adaptable with new growth directed towards extending the length of the bulb (into cooler soil) rather than increasing girth. The taste and texture of ‘White Icicle’ is considerably better than either Radish ‘Cherry Belle’ or ‘Polenza’. While the globe radishes themselves have slightly disappointed, the leaf production has been good and remained in excellent condition throughout. Picking in the early morning is advantageous in ensuring the leaves are turgid (fully hydrated). At other times, when harvesting the radishes, be careful to retain the tap root (which may be up to 100mm in length) and immerse the bulbs in cold water with the leaves still attached, to allow for the lost moisture to be replaced before use; this is essential if making pesto!
The three lettuces in Planter 2 have grown substantially in the last week, and Lettuce ‘Salad Bowl’ and ‘Solix’ now fully crowd the middle and outer planting rows. Lettuce ‘Red Salad Bowl’ continues to be slower and is yet to fill the inner row. Notwithstanding this, the condition of all three lettuces is excellent and the combination of colours is attractive. The length of time required for the three line lettuces to reach harvesting is as per the prediction of 6 weeks (42 days). The combination of cooler and hotter weeks during this period have clearly balanced one another. The lettuces will be harvested for 4 weeks.
Planter 3 contains a mixture of crops with different maturity dates. Turnip ‘Tokyo Cross’ F1 is growing well and the roots have continued to bulb up. However, the foliage has suffered some heat damage and minor attack by flea beetles. These create characteristic small irregular holes on the leaf surface. The plants are well established and the attack will certainly not be fatal. Rocket ‘Serrata’ continues to be harvested regularly with larger leaves removed in turn which is ensuring the plants remain relatively compact. Swiss Chard ‘Bright Light’ remains frustratingly slow with the disparity in growth between plants in the centre of the row and those alongside being maintained. Despite this, plants have reached sufficient height for the training system to be fitted.
The carrot, spring onion and beetroot continued to grow steadily, although a greater increase might have been expected given plants are now at their final spacing and because day and nightime temperatures have increased considerably. The beetroot, like the Swiss chard, remain uneven. The fitting of the plant training system to the spring onion has cured the problem of plants lodging.
We’ve taken the decision to reduce the harvesting period for the radishes from 3 to 2 weeks. At this stage, the crop is most suitable for making pesto from the leaves and this can be made and refrigerated for up to 3 weeks. This will allow the outplanting of our Dwarf French Bean ‘Purple Teepee’, which are more advanced after 4 weeks than would’ve be expected!
In light of the prediction of even higher temperatures in the coming week, it has been decided to fit a shade netting over the planter. This will prevent ‘scorch’ of the lettuce, which is otherwise very likely, reduce the possibility of the rocket bolting (flowering) and discourage blackbirds from uprooting the dwarf French bean when it is outplanted. Dark green shade netting fabric is made from UV stabilised woven polyethylene (80 grams per m2) and has a 50% shade value (do not use scaffold debris netting or windbreak cladding as these don’t have the correct shade value). The netting is available in 2m wide rolls and is sold by the metre. It is easily draped over both our four linear and four-square planters and should be supported by fitting training rods (extended to their full height) in the corner of each container. The fabric should not be in contact with the foliage of the plants. It should stay in position under its own weight as long as the fabric extends to the top of the frame on all sides. Although we don’t currently sell cloches made from this material, until we’re able to we think a home-made solution should be simple, and work just as well!