Category Archives: smallholding

NDVI investigations of compost-enhanced crops

I made a couple of NDVI images of the beans which had been greatly improved using compost compared to those grown without. The principles of NDVI as based on that

Generally, healthy vegetation will absorb most of the visible light that falls on it, and
reflects a large portion of the near-infrared light. Unhealthy or sparse vegetation reflects
more visible light and less near-infrared light. 1

Knowing that, it’s possible to see in the NDVI image that the compost-grown beans do seem to be reflecting more IR relative to visble light, I find this easier to qualify from the greyscale image Continue reading


  1. Understanding the NDVI PDF

Remarkable win on beans with compost extract

Last year we made compost and compost extract for use in the polytunnels. The extract was also looked at with the microscope. Most of the compost after making extract was used in polytunnel which has tomatoes in it. These look healthy and were praised by another local gardener, but there’s no control. However, we did have a control on the extract applied to the beans in another polytunnel.

If you look at the picture at the head of this post, on the RHS of the picture is the control. This is what we would have grown normally.

in the middle on the top you can just see a blue ribbon which is where application of the compost extract stopped. On the left are the plants where compost extract was applied to the ground, it ran out at the blue ribbon point. Same plants, same time planted, and the same set of seeds. The difference in vigour, height of growth and yield is remarkable and clearly to be seen. Continue reading

Seed saving beans

The Seed Saver’s handbook says beans are easy to save, so it seems a good idea to start out with them, in this case some Sutton Dwarf beans. The idea if you leave them to dry in the pods and then save the good ones. Beans are an easy win as they adapt over the generations to the local conditions; they don’t use insects for pollination and the book says the gene pool is kept wide to allow self-pollination.
Right off the bat the book says that

The first pods to form are the best for seeds. They are to be found at the base and are larger than subsequent pods, Allow these pods to dry on the bush, and choose those from the most vigorous plants. Such refined steps cannot be taken on a large scale where a whole field is combine-harvested and threshed.

Well, we don’t have a problem picking seeds out of the combine harvester we don’t use ๐Ÿ˜‰

the good bean seeds

the good bean seeds

The guys that wrote that book are Australian, and I guess they don’t have a problem with saying you need to store seeds at a relative humidity of 5%.

Closing the conservatory door at about 9 was a good move, though I am a long, long way from 5%!

Closing the conservatory door at about 9pm was a good move, though I am a long, long way from 5%!

So I am writing on the evening of what has been a reasonably warm sunny day and I see the RH starting to skyrocket to 50% by 10pm and realise that I need to close the door to the conservatory because the dew comes in the evening as the sun goes down, not in the morning. 5% is going to be a tough call in the UK, probably involving silica gel. Interestingly the Seed Saver’s Handbook says good airflow is more important that high temperature, and it should not go beyond 35C anyway.

long bean pods give the best results

long bean pods give the best results

They’re right about those lower pods – long beans are definitely the place to go for the size of the seeds. You have to be pretty discriminating about the seeds, however.

Continue reading

Using near IR to look for photosynthesis and plant health with NDVI

The NoIR Raspberry Pi camera comes with a blue filter to do near infrared photography – the blue filter ices the visible red but passes near IR which records as red, apparently.

NDVI image of something in the polytunnels

NDVI image of something in the polytunnels. Should have made a not of what this plant is ๐Ÿ˜‰ Anyway, more red and going to magenta white overload=more photosynthesis

NDVI (Normalized Difference Vegetation Index) is the near IR plus red divided by near IR minus red. Take a look at this image for the meaning of the colours – red, magenta and white is more photosynthesis, cool colours and black are less. Chlorophyll uses red but doesn’t use near IR which it reflects, hence the difference carries useful information.Lots more at Public Lab. Continue reading

Using the microscope to grade compost and compost extract

This is using Elaine Ingham’s microscopy techniques to investigate thermal compost – some of what I saw. I am at an early stage of being able to do this, so any errors are mine and not Elaine Ingham’s ๐Ÿ˜‰ The principle is to classify organisms by their morphology – aerobic fungi tend to have a colour, diameter wider than 2.5ยตm and/or have uniform septa. Spiral structures are bad, indiciative of anaerobic conditions, and ciliates (hairs all over the body) also indicate anaerobic – bad- conditions. Apart form the spirochete most of these are good.

This is on a 5x dilution, the recommended intial conditions (use 1ml of compost and make up to 5ml total with water left to stand so the chlorine has gone).

Composting win

If at first you don’t succeed, try again ๐Ÿ™‚ The requirements of Elaine Ingham’s thermal composting are quite demanding, keeping the heap at over 55C for more than three days to kill weed seeds and pathogens. The previous attempt got really close then seemed to dry out, this appears to be a issue with using a lot of woodchip which is a difficult material to wet. This time I used less of it.

more green material with this heap

more green material with this heap

I used a higher proportion of green material, and more of the high nitrogen clover too. I filled the wheelbarrows with woodchip and then added water until it overflowed, then left it to soak overnight

this achieved over 55C for three days - the dip is when this was turned

this achieved over 55C for three days – the dip is when this was turned on Thursday evening

After it had been over 55C for three days I turned this heap, wetting the material as it was turned over. I should be able to turn this again on Monday, assuming it holds above 55C

Composting – take two

Time to put some of the learning from the last time into practice, with thanks to Polly for help with wrangling the materials –

Raw materials

Raw materials

The clover which it the high-nitrogen component because it fixes N from the air is on the black plastic. Loads of wood chip is in the bin and the wheelbarrow. First we put sticks in the bottom to improve airflow because the whole point of thermal compost is to keep things aerobic

base of sticks to improve airflow

base of sticks to improve airflow

We needed to wet the material. In the video tutorials Ingham recommends standing the material in water overnight. We wetted is using a fine spray on the hose

Lucia and Polly soaking the woodchip

Lucia and Polly soaking the woodchip

A heck of a lot of material goes into a compost pile – thanks to Polly and Lucia who helped at the working party Continue reading