Thursday 6 March 2014

Late Sweet Peas

The sweet peas Lathyrus odoratus have germinated well and are growing on in the greenhouse.  I usually have them sown in October but this year I have waited until the end of  February before planting them.  It means that they will be flowering later in the year but that is no problem.

 I want to put up the sweet pea canes fairly soon - either this week or next.  The sweet pea bed has rye, tares and clover green manure growing on it so this will have to be dug in before the support canes are put in.  This bed had very thin soil with little organic matter.  I have added shredded material to the subsoil and a little horse manure to the top.  I am relying on the green manure to add more organic matter to the soil before I have to work it into the top thirty centimetres.  I do have some blood, fish and bone and might add this as well before planting the sweet peas.

The ground had not grown anything but Calystegia sepium  and Hippocastanum arvensis together with a little Elymus repens for about two years so I am hoping that this fallow period has helped the ground recover from intensive cropping and be ready to produce some good vegetables, fruit and flowers.

When raspberries Rubus idaeus have been growing in the same ground for several years, it is very difficult to get new plants to grow where the old plants have been taken out.  It is the same for roses.  It also seems that rhododendron plants have associated mychorrhiza that make the ground unsuitable for planting anything else than other rhododendrons for years after they have been removed.

Now if we look at an allotment where the same crop is grown in the same place year after year, there is a loss of vigour and the plants are not healthy.  Is this due to the same soil sickness that we see with raspberries and roses?

I rotate my crops religiously every year in order to avoid this reduction in harvest but I have done it in the understanding that different plants take different nutrients out of the soil and at different depths.  This may still hold true but it might also be due to 'soil sickness' brought about by mychorrhizal fungi associations.  I use a generalist mychorrhizal mix when I add spores to planting holes.  These mychorrhiza infect a wide range of hosts so I think that they would not aggressively prevent plants growing in a particular soil.

It does give me another reason to rotate my crops though.  So I will continue to do so.

Although it has been quite warm over the last few days, none of the other seeds have decided to germinate.  I am quite glad because I don't really have time at the moment to prick out and transplant.  I will let the broad beans grow on until they are about ten centimetres before I plant them in the allotment.  I do have room for them now but keeping them protected will bring them on and make them stronger for putting out.  If I eventually get my cold frame from the old allotment, then I will harden them off in there.   Tomorrow I will make some progress on trench thirteen because there are few perennial weeds where I am digging except where the path was.

Two things that are useless on an allotment, 1. grass paths, 2 wooden curbs.

The grass paths cannot be used in wet weather, encourage perennial weeds and need constant maintenance. The wooden curbs rot.  So use concrete two foot square slabs for the paths and concrete curbing.  They do not rot.

ALSO USE BLACK PLASTIC NOT BLUE PLASTIC SHEETING.  I am still picking out flecks of blue plastic that has crumbled into my top soil.  I can't even sieve it out using the bread tray because it breaks into tinier pieces as I am sieving.

Up early tomorrow to get an early start.

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