Harvesting to Dates

[Westi]

Hi

Normally I just watch and harvest as things appear ready,
however lately I have been talking to people who sow and
harvest on particular dates. Some is date from sowing but
others is handed down advice.

Does anyone harvest to date and if so do you mind sharing
success and dates as I would be interested in trying it?

Thanks Westi

[Chantal]

I've always been told to plant shallots on the shortest day and harvest on the longest day and although I'm sometimes a day or two out it's usually pretty close.

[richard p]

ive never known a sucessful gardener that ignored the effects of the british weather.

[alan refail]

Hi westi

I thought at first: Blimey, Dorset must be hot if they're discussing harvesting dates

What crops do your "people" harvest on set dates? I'm sure most people harvest/pick as and when needed/ready. Even the shallots - what if the ground is rock hard on the shortest day, or soaking wet?

Having said that I must confess to starting to lift early potatoes exactly two calendar months after planting, but that only works with Red Duke of York grown in this particular spot in NW Wales. I wouldn't put it forward as a guide to digging any other variety anywhere else.

[PAULW]

I thought at first: Blimey, Dorset must be hot if they're discussing harvesting dates

Alan it is hot and very dry can you share a little bit of all that rain youv'e been having it hasn't rained for weeks down here apart from the twelve spots we had on tuesday

[Primrose]

In uncertain climates like ours I'm sure it would be pretty unusual to be able to put a date in the diary and say "This is when I'm going to harvest my beans, tomatoes, etc. So much depends on the growing conditions and weather, and I'm sure the seed packet advice is only given as a general indicator. In any case, so many vegetables, especially beans, courgettes, tomatoes, etc. have continual harvesting dates from one plant over quite a long period, especially tomatoes on the same truss which ripen over a period of several days. I always wondered how the supermarkets are able to sell vine ripened tomatoes where every tomato on the truss seems to have the same level of ripeness. It never happens like that in my garden!

[Johnboy]

Hi Westi,
The harvesting by dates is really only an approximation and is really to give you an idea as to when you might expect to harvest. There are really no hard and fast rules.
I take the example given by the seed houses that with Summer Broccoli varieties crop 121 days after sowing. You read that and then swallow a small pinch of salt if you are at all wise!
JB.

[FelixLeiter]

Timing of harvesting is all dependent upon what commercial growers term day degrees, defined thus:

Accumulated day degrees = ((max + min daily temperature) / 2) - base temperature

Base temperature is the minimum temperature at which growth will cease, usually around 3ºC. This may seem like something over which we have little control, which is true for all but glasshouse growers, but by monitoring temperatures for the duration of a crop it is possible to time the optimal application of pesticides and fertilisers. It is also possible to select varieties best suited to a climate based on their day degree index. For instance, a pea variety which requires 120 day degrees will be ready for harvest earlier than one of 210 day degrees. We're not used to seeing these values printed in seed catalogues in this country, but in the US, a grower in Vermont is more likely to want very different characteristics from their varieties than one in Alabama, and day degrees is a good guide.

As for harvesting at a particular date: I've never quite managed it. Close, but no cigar, usually.

[Johnboy]

Hi Felix,
The calculations you mention are not used in UK and certainly do not represent what is written in British catalogues.
This is a case where it is wrong to take advice from American catalogues.
My example I mentioned for Summer Broccoli of 121 days means just that and this is what breeder of the seed has passed on to the seed house or the seed house has found in it's own field trial and this in days.
Remember that in the US they span through ten temperature zones and at most we go through two so they have to use a more sophisticated system.
By even attempting to use the US system here it would do more harm than good and cause very great confusion.
JB.

[Colin Miles]

Whether this calculation is right or wrong it is nevertheless very interesting to me. I have an automatic weather station and log temperatures, etc., every 10 minutes. So I have an accurate record of the max, min and mean temperatures which I monitor using a program I have written. So maybe it calls for another program to monitor the temperatures between sowing and harvesting. I shall report back - maybe in 10 years time!

[Johnboy]

Hi Colin,
I would be prepared to bet that if you do the readings for a ten year period that no day in that period in any year would even match with the same day in any other year! This is British weather we are talking about.
I too have a weather station that is not automatic but gives me the outside temperature and also another that gives the temperature and the humidity in one of the tunnels. These are now some twenty years old and really should be replaced but as I am now well retired I very much doubt that I will bother.
Who was the manufacturer of your station? Mine were paper labels which have now disintegrated and I now cannot remember who made mine.
JB.

[Westi]

Hi All

Being from Aussie we also have zones and when
I saw how small the UK really was I kinda understood
why they weren't here. But the weather variations
even on this small island are amazing. I'm slapping
on Factor 30 and people only a few degrees north
are freezing. I agree it is difficult to sort but you
would think seed manufacturers would make a bigger
effort to push the days to maturity - it is only in the
small print and unless you are experienced you pick
from the lovely discription of the finished product not
the suitability for your area. Speaking from experience
here!

Westi

[FelixLeiter]

Hi Felix,
The calculations you mention are not used in UK and certainly do not represent what is written in British catalogues. This is a case where it is wrong to take advice from American catalogues.

Well indeed. It is, and I don't, and I wasn't suggesting anyone else does, either. I think we're all sensible enough of the vagaries of the British climate to know what's appropriate.