Make Your Own Potting Compost

Charles Dowding

Either buy compost for propagation, or you can make it. With homemade you know what's in there. See possibilities here: having good materials to make your own needs forethought and that you made suitable compost.  Why compost not soil? Compost has a fine crumb structure, good aeration, decent drainage. Although the soil at Homeacres is great soil, it is dense and wet in cells and pots.  What makes a good mix?! In order of importance: 1 Nutrient density,  2 Good drainage, 3 Holds moisture, 4 Weed free.  I show three possible main ingredients sieved to 4mm,  1 Own compost  2 Worm compost  3 Woodchip compost - must be dry enough to sieve, makes manure difficult PLUS in small amounts (and why) are soil, perlite/vermiculite, sand, minerals like seaweed powder, wood ash, basalt dust.  00:04 Any new sowings are for trial purposes! 00:38 Multisown radish, 5 seeds per cell 00:54 Result with homemade compost when it's good 01:39 Dramatic comparison between 2 different composts 02:04 What is digestate 'compost' 02.31 So-called 'organic' compost 02:49 My composts for this video 03:00 Result of sieving homemade compost to 12mm / half inch 04.20 Result of sieving composts to 4mm / 1/6in 04:58 Composts need to be dry for sieving to work 05:58 18 month old compost 4mm 06:25 Three year old wood chip to 4mm 07:07 Worm compost to 4mm, includes a little soil from being on the ground 07:58 How to run worm composting at different scales 09:17 Be creative, according to what you have available 10:10 Amazing weight differences of soil, compost, vermiculite 11:29 Wood ash 11:51 Rockdust from basalt / volcanic 12:38 3 kale plants, 6 months in 2L. pots of different composts 13.15 (spent) Mushroom compost 13:44 Propagation fun 14:16 An easy way to mix ingredients  Children's Gardening Book https://charlesdowding.co.uk/product/no-dig-childrens-gardening-book/  Online propagation lessons, short course https://charlesdowding.co.uk/product/skills-for-growing-online-course-module-2-seeds-sowing-and-planting/  We did more compost trials in the greenhouse last spring https://www.youtube.com/watch?v=XnoZ4jvrY5g And this is one of me How to Propagate https://www.youtube.com/watch?v=veevYVUBakA  You can join this channel by paying a monthly fee, to support our work with helping gardeners grow better, and to receive monthly videos made only for members: https://www.youtube.com/channel/UCB1J6siDdmhwah7q0O2WJBg/join

Transcript

00:01How to make your own potting compost. It's late January and we're heading up to a really busy

00:07season of raising plants propagation and for that it'll really improve your growth in the garden

00:14all year if you can get a good potting compost that you can use to fill trays and raise lovely

00:20strong plants right the way through the season in fact and in an undercover space that enables

00:27a high success rate especially if you get a good compost so we've been doing some trials here even

00:33though it's January just to see to trial a few composts and and to be able to show you so

00:38for

00:39example this is multi-sown radish in a one of the trays I designed that's a CD60 which has quite

00:47small tapering cells and that means you don't need much compost but if you don't have much compost

00:53it needs to be a good one and well I think we've got some good ones here but even so

00:57there's an

00:58interesting difference between the two so one end is is a purchase compost we're still good there's

01:05nothing wrong with it but that's the homemade and you know I'm really quite surprised actually that

01:09how good the homemade compost is but it's quite special I'll explain that in a minute we're going

01:15to have a look outside at all the different materials ingredients you could put in there

01:19and if you can get a good compost in in a tray like this so these are multi-sown average

01:25three

01:26or four radish per cell there's 60 cells there there's 200 radishes in there you know it's like

01:32wow in a small space you can raise a lot of plants especially when the compost is good and reliable

01:38here by contrast we have two different composts and how would you feel if that was the one that you'd

01:47sown it's like this one is is the one I've been buying um Pete's Pete free compost it's really good

01:56and these broad beans were sown about a month ago and they've been in here without heat but it's been

02:02quite mild and this one is one it's actually not sold as a potting compost so you could say in

02:08a way

02:08it's not a fair comparison but nonetheless for me there's something wrong with this one

02:12it's made from digestate which is generally a material I would avoid because it's a little

02:18bit unreliable I've found this is just what I found and some of you might be doing all right with

02:23it but

02:24I've not yet had a success with anything made from digestate read the small print they don't always say

02:28clearly when you buy a compost it sometimes this one's actually called organic compost you know it's

02:33like sounds really good and so that's we'll look at this more in a later video that we're going to

02:39put

02:40up about filling trays next week so let's have a look at some possible ingredients there are some

02:50beautiful materials here for making a potting compost and to get them to this state we've done a bit of

02:57sieving so there are sieving options like how small do you want it this is 12 millimeter which does

03:06still have some larger pieces of whatever was in the compost in this case bits of wood and twiggy stuff

03:13and that goes through a metal sieve which I found last year online it's pretty clever so we did it

03:20back

03:20in the 80s actually we had a metal bed frame at 45 degrees and you throw stuff at it and

03:25the fine stuff

03:27falls through and the larger stuff stays at the front and trickles down to a pile and you've got the

03:33nice

03:33this stuff in this case that's 12 millimeter sieve so you can see it's pretty nice actually

03:38that's homemade compost as it happens and this though would not be ideal still for small module

03:47cells for example a bit too much of that sort of stuff which is it's not going to hamper growth

03:53even

03:53though it's wood there's not too much of it but it's not got a lot of nutrients in we need

04:00two main

04:01things we need enough nutrients because we're using quite small volumes or quantities of material

04:08compost and we need drainage so the drainage actually would be helped by that but if you know

04:16you could in theory make a potting compost that you know woody material it'll drain brilliantly but it

04:21won't grow much plant so we need a bit of both and we've been using this one actually this funnily

04:29enough

04:29it's slightly ironic that's from a wormery a plastic wormery and the other is the worm compost falls

04:36through and also the worms can come up through this you stack these up but basically that's four

04:40millimeters which is around a sixth of an inch and and that lets through shaking so it's a bit hard

04:50work

04:50to get a lot but it's very powerful it's very possible to get a decent amount in fact Adam was

04:55doing it last

04:55week when the compost was slightly frozen and that worked really well it stopped it getting soggy because

05:01if it's too wet and soggy a sieve like this won't work so thinking ahead if you've got some compost

05:08that

05:08you think you might want to sieve in a week or two put it somewhere dry even in a shed

05:14on the ground

05:14spread it out and let it dry a bit before you try to sieve it so this is just to

05:22emphasize this is a

05:23tray I was showing you just now and the radish so that it's not holding together very well this is

05:30a

05:30whole nother thing that we'll look at next week but here are some very nicely rooted radish but you can

05:38see that's four plants of a decent size growing in not much compost that's the the point of what we're

05:45looking at here is how to achieve that uh those radish are ready to go in the ground by the

05:50way they're

05:52quite big so um different compost that we've sieved and what they look like this is homemade and it's 18

06:02months old this is as nice a homemade compost as I've ever made and that will make that'll be good

06:10for potting I'm sure of that we did some trials last year comparing different compost more in isolation

06:14just to see how they did and actually this one started a bit slowly finished very strongly and I'm

06:21pretty sure the slow start was from drainage issues when seedlings still have very small roots and as the

06:28root system developed and got stronger it mattered less but we are mostly looking here at something

06:34for very small roots so we that's where the drainage is so important and where the wood chip this believe

06:40it or not is wood chip sieved to four millimeters actually about three years old it's some I got

06:46delivered here two years ago when it they claimed it no last year and they claimed it was two years

06:51old

06:51already you never quite know and the way it doesn't matter it's more what it looks like but if you

06:54can get

06:55it looking like that well that's quids in and I'm finding this works really well as an adjuvant to

07:02improve drainage holds air in the compost as well as providing some goodness so these are all

07:08possibles and here's another one an amazing possible this is worm compost it's first time I've specifically

07:14made worm compost we've had you know worms that so that's a senior fatigue the worms are not the same

07:20as

07:20the big fat pink earthworms these are the small red wrigglers wiggly wigglers or tiger worms red

07:27branding one very similar and they're the ones that just appear when you have a compost heap if it's

07:32not too hot so we don't get them in our main compost heaps until towards the end when the heat's

07:38gone

07:38and that's great then they they come along and you kind of they'll turn it into worm compost if you

07:42left them long enough or what we do over there is have a dedicated area for worm composting where we

07:47don't add too much material at any one time so it never gets too hot they keep eating and through

07:53the year you're adding adding material on top the worms are rising with that adding food material and

08:00just three weeks ago we actually we scraped off that top layer finally after ten months of doing that

08:05and put them onto one side that the other side of the bay and that's now this year's wormery and

08:12lifting up the black plastic you see usually you see the worms there sometimes slow worms actually as well

08:17and at the moment though because it's quite cold and we're having a frost every night so the worms are

08:23deeper down and you don't always see them but they're still there so this is average probably six to eight

08:30months old worm cast basically you know that's beautiful that's rich but what we found last year and I

08:38noticed how in different mixes different proportions of worm compost that around 20 percent look to grow the

08:46best plants rather than say 100 percent I did 100 percent that wasn't so good I think again maybe a

08:52drainage issue which is why I'm actually quite impressed by these radish here how well they're

08:56growing in 50 percent that's 50 percent of this worm compost and 50 percent wood chip that is working

09:04that's a mix that is working for me at the moment it's not like you I can give you the

09:10perfect recipe

09:10that's going to work every time because your worm compost will be different to mine your wood chip will be

09:15different to mine so you've got to play around a bit it's a chance to be creative that that's why

09:20keep in

09:20mind those two basic things you need enough nutrients you need decent drainage and for drainage that's a

09:26reason not to use soil believe it's not that's that's homeaker soil it's looking as nice as it's ever

09:31looked that's because we've had some frost and so this is actually a frost what's called a frost tilth

09:38farmers love it you know if they plough their fields frost people who dig their ground love it you've got

09:44lumps

09:44and then the frost breaks them up you just touch it with a rake and it all goes oh beautiful

09:49that

09:50though in my view that's not a stable tilth you know if it then rained and you walked on it

09:54it'll

09:54all squash down again and that's the difference to no dig where you've got the compost on top

09:58but soil is a possible addition I would say in small quantities again we noticed last year with the

10:03trials maybe 10 percent something of that would if it's really good soil like this could be up to 20

10:09percent it's very interesting also the difference in weight there's a lot of material in there so we

10:17were just checking on the scales and this one roughly in a 10 liter pot that weighed in at 6

10:22.9 kilograms

10:24that's meaning that's 70 percent weight you know if that was water if that was full of water that

10:30would weigh 10 kilos water is so dense and heavy so you know we're getting close to that and the

10:36wood chip

10:37compost by comparison much lighter that was 3.8 3.9 kilos and the lightest one of all is this

10:45which

10:46is clearly not soil or compost that's vermiculite which is a kind of expanded rock and it's it's as

10:55far as I'm aware that it's a natural product you know it's not a plastic or anything like that

11:00um another version would be perlite similar my mother bless her in the old days she used to use

11:07some balls of polystyrene which yeah wouldn't be so keen on that now but the the idea is the same

11:12which is to hold some air in the mix and I would mainly think of using this one where I'm

11:18using a bit

11:19of soil to balance those two things whereas the very successful radish there doesn't have any of this

11:24you know this is not an obligatory but it's a possible option and likewise another option could

11:31be wood ash that's from my wood burning stove that's quite rich in potash I tend not to worry

11:38too much about nutrients because these I'm finding all have it more or less good but if you wanted a

11:45bit of extra potash you know this might be more actually for if you're growing tomatoes in containers

11:49that kind of thing and then we got rock dust oh this is really heavy partly because it's wet

11:55that's basalt rock volcanic rock and that's claimed to have lots of trace elements and minerals

12:03I'm still a little bit cheery's out on this one I've used it with not huge success but it's it's

12:11I will sometimes put it in just as kind of covering all bases kind of idea uh when I would

12:16prefer to

12:16have actually from that point of view for trace elements minerals is seaweed I haven't got any

12:20here you can buy seaweed in powder and if you can get it as a green powder there's a company

12:26in

12:26Ireland called better plants I think who sell seaweed powder make it in a very low heat weight and I

12:34had good results from that last year used it all up now and there are other options I haven't

12:41mentioned in fact these three kale plants give you an idea these believe it or not have been growing

12:48in these pots two liter pots for six months without any feeding or anything that's the result I would

12:56say they're all good compost in their own way that one actually is cow manure so well rotted cow manure

13:01it

13:03was probably about 18 months old when it went in the pot it's not sieved that's the homemade compost

13:08but a slightly more woody version than what I just showed you and that was sieved to 12 mil not

13:134 mil

13:15and this very strong plant is from mushroom compost you know there's another option for you if you can

13:21get some mushroom compost I would age it a bit so usually when it's sold to you it's it's a

13:26bit fresh

13:27and if you left it two or three months so the results would improve and then probably don't need to

13:32because they've done all that just break up the lumps and there's options for you I do

13:39propagation course online you could find out more there about how to raise plants and also in my

13:46children's book which has recently come out there's a bit about propagation raising plants that really

13:51fun thing to do with children and we'll put links to all of that on on my website we've got

13:57a course here

13:58at the end of March and in propagation just an afternoon course and I'll see you in the sequel

14:04to this video which is about actually how to use these composts and what to put them in there's one

14:12thing more I've remembered actually I've not actually made a compost so I'm just going to do this now

14:18I'm going to and I'm going to show you a way we can make it very nicely maybe not all

14:23of these this

14:23is 10 liter pot I put about eight liters of the homemade compost which it I'll put about the same

14:34and then the mushroom compost I will put a smaller proportion sorry the worm compost

14:41maybe about half the pot there yeah it's amazing I'm feeling those granules of ice in that the it's

14:49being very cold here overnight soil well I need two hands just a little bit I notice actually there

15:02was a bit of a bindweed root went in there this is something to watch out for we saw perennial

15:10weed

15:10roots and also seeds it could be some seeds weed seeds a little bit of vermiculite just to kind of

15:21balance the soil two handfuls that'll do a bit of rock dust just to see and wood ash I don't

15:33think I'll

15:33bother so a really good way to mix is pouring because when you pour you get a kind of gradient

15:46a slope and what's in the bottom of the bucket comes out quite increasingly halfway through so you

15:54each end goes to another end eventually and what's in the middle goes to both ends as well and just

16:02doing this four times you could do it more about doing it another time wouldn't hurt but I'm noticing

16:09now vermiculite is a good way to tell the vermiculite is appearing throughout and we're getting a nice

16:18steady mix so there we are two decent buckets and we now have a very nice compost for propagating you

16:29could use this for sowing actually because it's it feels nice and light and also for raising plants

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