Checking the soil. 

Not wanting to go on about it, but the Pith Necrosis in my tomatoes (you can read about that >HERE<) has been on my mind.  One of the things that made the conditions ideal for the disease was the soil was too nitrogen rich.   I’ve been pondering this a lot.   The general instruction to gardener is to add organic material like compost and well-rotted manure to the garden between each crop.  Or grow a cover crop to replace the nutrients taken up and add ‘much needed’ organic material into the soil. But it isn’t all that clear as to how much is too much or even too little for that matter until it is too late.   You only really find out the truth when your plants are growing  and begin to show signs of poor health.

Mustard Seeds
Mustard seeds are proving to be a good measure for the quality of my soil.

This can often be mistaken for disease at first, rather than a nutrient deficiency or excess and so various remedies can be thrown at a plant already suffering from something else. And as an insult to injury pests and disease see a weakness and muscle on in and there you have it – a bit of heavy handedness with a bag of poop and your crops are ruined.

Mustard Seeds
I carefully weighed out the mustard seeds for each bed. I suspect there were too many for the size of the patch, but with them all being the same it would still result in equal outcome.

Adding too little can be easily fixed by feeding plants regularly throughout the growing season but adding too much is like adding too much salt to your mashed potato.  You can’t take it out again.  And it isn’t like all these excess nutrients are just sitting around in the soil like it is a supermarket waiting for the plant to take them up.   There is some complex chemistry going on in the soil and sometimes what can show up as a deficiency in the plant is because some other nutrient is out of balance and blocking the path to absorption and so there is enough of what the plant says it isn’t getting, but too much of something completely different.

Preparing the ground
I used an old seed tray to mark out the size of sample patch and removed all the lumps, bumps and other unwanted bits and bobs.

So, we need to take care when adding things to the soil willy nilly.  It isn’t like that overindulgent grandmother trying to fatten us up out of love because we look too skinny.   We may love our gardens but the more the better doesn’t apply when feeding the garden.   We need to get to know our gardens, and this can take time and trial and error as each season we refine what we have learnt and make adjustments.

Preparing the ground
I gave the dry soil a good deep drenching with water to give the mustard seeds a good moist foundation.
Preparing the ground
Then I sprinkled over the mustard seeds within the grid and sieved over seed raising mix to ensure they had good contact with the soil and to hide them from the birds.  And then we wait.

One easy way to know what your soil needs is to do a soil test, however for most home gardeners this is cost prohibitive so I came up with a bit of a plan to assess the state of the soil in each of my garden beds.    I got the idea from the mustard cover crops I grew last season.   One bed – the last to be filled with the dregs of the soil pile didn’t do as well as the cover crop in a neighbouring bed.  It was the same seed grown with the same attention but with a completely different result.  It did explain why that bed hadn’t performed as well that first season and as a result I gave it an extra bit of love at the start of the growing season and the crops did much better.

The germination stage was mixed results. Some beds were quite patchy….

But it was the mustard seed that was the tip off.  So, I did a little experiment.  In each bed I marked out the same sized plot and weighed out the same amount of mustard seed to go into each patch of the garden.  They were treated exactly the same way – even on the days I forgot to water them.   Then I took note of the germination rates and then looked at the growth several weeks later.  I didn’t need to see out the whole life cycle of the plant because after 4 weeks the results were apparent.  I could see at a glance which beds were doing ok with good steady growth, which weren’t ok with pathetically spindly growth and which were doing too well with loads of excessively lush growth.

… and other beds were abundant and lush.

This will give me a good plan going into the next season.   The ones doing well I will just give a light top up, using a proprietary packet of something following the directions on the pack, making the safe assumption that the dose will be ok as they wouldn’t want your garden to fail or you won’t use it again.  A trusted brand has my gardens best interests at heart.

Mustard plants
Just over a month later the results were in. Many beds seem to be in good shape with a good steady even growth.

The beds where the growth is not great, I’ll throw everything including the kitchen sink.  I’ll grow a cover crop and then add compost and well-rotted manure and do what I can to boost the obviously poor soil.

Poor mustard plant growth
Several beds have shown poor growth, but to be honest I think I expected it from these beds as they weren’t exactly doing all that great this season and may have been neglected a little during the seasonal enrichment between crops.

And the ones with the over exuberant growth – well I’ll do nothing.  They clearly don’t need anything.  But if it does look like it is really too much then I’ll grow a cover crop and instead of digging it in, I’ll add it to the compost heap where I can redistribute those excessive nutrients.

Too lush mustard plant growth
But not really surprising was the number of beds with very lush growth. The leaves are big, the stalks thin and weak. These are the ones with the most insect damage. It is important to note most to these lush beds have already had a season of growth and are still lush and not in the expected exhausted state. It would seem I’ve been a bit heavy handed with my soil enrichment, but now I know where to make changes.

The other thing I’ll pay closer attention to is, not all crops are equal, and some won’t need as much love as others.  Carrots for example really don’t like a rich soil and so I’ve always avoided adding compost or well-rotted manures to their beds.  But crops like corn – well it is a large plant and to get that large from such a tiny seed, it seems logical that it would need a lot of goodies in the soil to feed it.   Leafy greens like it heavier on the nitrogen than for example peas, where potassium and phosphorus would be more appreciated for their flower and seed production and considering they take care of their own nitrogen needs.  But the leafy greens wouldn’t need anywhere near as much nitrogen as the corn.

Come again soon – preparing the garden for next season is clearly not a one size fits all solution and I’ve got some work to do.

Sarah the Gardener  : o)

5 thoughts on “Checking the soil. 

  1. Mustard was the main cover crop in the formerly vast orchards that once occupied the Santa Clara Valley. It naturalized after the orchards were abandoned. Of course, it is now as gone as the orchards are. It still grows wild around here though. I no longer think of it as a cover crop. We collect the greens.

      1. There is a legend that Father Junipero Serra tossed a few mustard seed out as he rode between the Missions on or near the coast of California during the Spanish Period, in order to be able to find the road later on. Travelers just followed the bright yellow bloom. By the time it got too dispersed to follow, the road was well worn. I find that doubtful, since it spreads so readily, and would not have always been in bloom.

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