Someone got the water out, added fertiliser and hey presto, Ben Bernanke’s “green shoots” became something a bit more substantial in the US home building industry: the biggest rise in 20 years in new home starts in the US.

But as in most cases, the headline figure was not the story: it was how it was arrived at that tells the tale.

Housing starts for privately owned new single or multi-family dwellings (home units in Australia) jumped by a very sharp 22.2% to a seasonally adjusted annual rate of 583,000 units in February. The rise ended seven months of unremitting falls. The rise was much higher than the revised January estimate of 477,000 annual starts and the market consensus forecast of 450,000.

And in another bullish development, permits to build new homes, an indicator of future activity in the housing sector, rose 3% to a seasonally adjusted annual rate of 547,000 in February. That was better than January as well and the market forecast.

The news helped send Wall Street higher as investors piled into home building and supply stocks. For that reason, watch Boral and James Hardie go for a run here this morning after their American operations have been battered into the red by the US housing slump

But a note of caution is needed:

The increase in new home starts was driven by an 82.3% surge in multi-family dwellings: analysts said the rise reversed the losses of the past three months. It was as though someone had found a whole lot of missing approvals and shoved them through various local government approvals bodies in February.

But there was a speck of green in the single home sector: they rose 1.1% in the month and permits were up as well.

Single-family starts edged up to 357,000 from January’s 353,000 and permits rose 11% to 373,000 from 336,000 a month earlier.

But encouraging as it was, the the industry is still moribund, like the rest of the economy.

Compared to a year ago, housing starts were down 47.3% last month and permits were off an eye-watering 44%.

But it is a sign that the low interest rates that the Fed has been forcing into the financial system through various processes, such as lending hundreds of billions of dollars and buying certain types of debt, is starting to have an impact.

But overnight several thousand more jobs were lost, including another 2000-plus at Caterpillar. It’s a reminder of the realties of the US economy at the moment.

US producer prices rose by less than expected in February, up 0.1% compared with a 0.8% rise in January.

So more green shoots, as the Fed chairman said on Sunday night in a TV interview, a few scattered glow worms in the dark tunnel, or just a couple of tantalising false dawns? Retail sales seem to be steadying, the banks are finding it easier to make money when they can borrow from the Government at next to no cost (next they will be thinking of ways of paying themselves more money because they are such tremendous business people for being able to do the basic of banking) and tensions in credit markets continue to relax.