My first guess would be that the compost you are adding may not be fully decomposed. In spring it will tie up the nitrogen and the plants will not grow. By summer the compost breaks down enough to release the nitrogen and things will start to grow.

Some crops such as spinach are sensitive to low pH but since the plants grow later in the year pH would probably be ok. I would try to add a high nitrogen fertilizer and see if the spring crop grows better.

Without telling us where you are, that question is really hard to answer. I know places where they call "spring" the time of year when snow is melting on the ground. No seedlings will grow fast in those conditions. Is this an issue of planting in the spring versus planting in the summer, or is it an issue of the kinds of vegetables being planted?

My location is in my icon to your left. The compost is finished I buy it from a local rockery. I plant the seeds according to the local master gardener table. First couple years they did well now not so much. I wondered if the old bark mulch that got mixed in with the new compost would tie up nitrogen but then wouldn't that slow down my tomatoes too? They are growing really fast.

Whoa. That's not where I expect to see a location, and I can barely read it. But yes, I've gardened in the Bay Area, so I know a bit. Your springtime should be quite favorable to gardening. But I agree that the issue may be nitrogen, as leafy vegetables need a lot of that. You might get your soil tested.

Unrelated to your problem but occasioned by someone's reply: can you get your hands on a Sunset Western Garden Book? Read about your zone? I am just asking. I don't even know if they print it anymore.

What sort of nutrient supplements do you use and how regularly do you apply them? It may be nothing more than nutrient depletion issues but you don't indicate any nutrient supplement. Compost is a soil amendment not a nutrient source unless you have an active soil food web and even then it only provides some of them - not nitrogen - and only in small amounts. A soil test would go a long way toward telling you what is needed.

Tomatoes actually aren't big nitrogen users so no insufficient N would not necessarily show in tomato plant growth.

Dave

Maybe that is the issue then. I till in the finished compost every year and there are worm towers in the beds. The worms do make castings around the towers but mostly in the towers so I scoop it occasionally and mix into the bed. Otherwise that's it. What is a good recommendation for just nitrogen to see if that is the issue? I have ammonium sulfate for my blueberries 21-0-0 but that acidifies soil as well.

If your soil is alkaline, ammonium sulfate would be good to add. I would think out west it would tend to be alkaline, but that might not be the case. Ammonium sulfate can burn the roots, especially if applied on dry soil. If it is clay soil, a one time addition of ammonium sulfate will not hurt even if the soil is acidic, to see if that is your problem. Some organic fertilizer can tie up nitrogen for the short term.

The problem with heavy springtime application of nitrogen is that a lot will be left in the summer. That will make for heavy tomato foliage, but not a lot of fruit. On reading back, Gary's idea that you may not be adding compost that is fully decomposed seems smart. That would cause a nitrogen deficit in the spring, that would eventually correct itself. That could explain a lot of what you're telling us.

The best strategy for applying nitrogen is to use split applications. That is, not the entire season's worth all at once.

Contact your county's Extension Service office for help with growing veggies in your region.

Locate that office with this interactive map:

http://npic.orst.edu/pest/countyext.htm

Here's some of their info:

http://cagardenweb.ucanr.edu/Vegetables/?uid=8&ds=462

I fertilize about every 2 weeks with a side dress sprinkle of composted Turkey manure, it's pellets 4-6-4, 1 pound per 1000sft. And I always load up the beds in the late fall with chicken manure from my hens.

The compost is black/finished. I don't think ammonium sulfate would hurt that much. Our soil is higher pH and we have to use irrigation water (higher pH) all summer due to no rain.

When I was in west Texas, it was recommended to use ammonium sulfate so it would slightly lower the pH. Since you use water that is high in pH, not only will it not hurt, it will actually help the pH.

I would apply a little at a time until the plants respond. In containers I use 1/2 teaspoons per gallon once a week. For your situation I would use 1 teaspoons per gallon once a week until the plants starts to respond. Do not let the ground dry out too much before you apply the fertilizer. I have burned the roots on blueberries by applying when the plants were dry.

I have a granular form that I got at HD. It's for lawns I guess. I toss the granules on top this time of year because the rain will dissolve them, and if it's raining the soil will be saturated. In the dry season I have to be careful and make sure the BB's are irrigated before I add dissolved AS to them.

Just remember that sunlight can break down the ammonium sulfate. If you put a handful of fertilizer out on bare ground and it does not rain for a week, 50% of the nitrogen will be loss. If it is incorporated this will not be a problem.

I've never heard that about ammonium sulfate and sunlight. Got a reference for that? No such instructions on lawn fertilizer that I can recall.

But big-box lawn fertilizer is mostly urea, I think. Certainly urea, if just sprinkled on moist soil, and not watered in, will lose a lot of nitrogen.

In all the granular fertilizer, the nitrogen can volatilize and be released into the atmosphere due to many factors. I learned that years ago when a got my nutrient management specialist certification. Dr. Feagley, Texas A and M Soil Specialist taught the course. They do have nitrogen stabilizers that have become popular that will protect the nitrogen from breaking down for a week or more, depending on how much they apply. That is one of the main reasons they always suggest incorporating by tillage or irrigation. Sunlight and moist soils are two of the biggest culprits.

The worse thing to do is apply fertilizer to a wet bare soil. A heavy dew will also cause the nitrogen to be released. If it is applied to a pasture, the nitrogen will be protected somewhat since it is shaded. I have heard you will lose 50% at two weeks. Saturated soil can also cause nitrogen to be released.

If you receive 1/2 inch of rain, that is enough to get the nitrogen into the soil. Anything less and it can cause more nitrogen to be released. If you are not expecting rain in the next couple of days, it is best to wait or incorporate nitrogen fertilizer. In my area, all the farmers watch the weather forecast and the day before a rain is forecast, they all try to buy the fertilizer and rent the spreaders to get it out. They really complain when the weatherman forecast 100% rain and still do not get a rain for a couple of weeks. Basically, they wasted half their money.

I sense another urine discussion coming up.

What was it? 1 cup to a gallon...

Gary, that is correct about urea and wet soil, but I'm pretty sure it can't be true about sulfates and nitrates. Ammonium nitrate is a favored fertilizer specifically because it is NOT volatile. I think if you heat it up, you can volatilize ammonium nitrate into N2O, but that takes a lot of heat. But combined with water, it just dissolves into ammonium and nitrate ions, which are not gases. Even for urea, I'm pretty sure that sunlight doesn't have anything to do with its volatilization. Now, the volatility of moist urea does depend a lot on temperature, so if sunlight is warming the soil, that will make a difference.

Now, to the extent that regular lawn fertilizer is partly urea, I do find it odd that application instructions that I've seen don't caution people about just throwing it on wet surfaces. I suspect the reason that lawn fertilizer is a combination of ammonium nitrate and urea is that ammonium nitrate by itself is a powerful explosive.