The Senate Budget Committee yesterday, drafted a 1978 federal budget with an overall spending ceiling of $459 billion, close to the level set by its House counterpart last week.

But because the Senate committee is less optimistic about economic growth during the federal spending year beginning Oct. 1, it projects smaller tax collections and a bigger deficit than the House.

The Senate budget, which will go to the floor next month, anticipates a deficit of $64 billion on revenues of $395 billion, while the House Budget Committee says revenues would be nearly $5 billion more and projects a $58.6 billion decicit.

In his latest budget update last month, President Carter called for 1978 spending of $462.9 billion, with revenues of $401.4 billion - the most optimistic assessment of the three - and a deficit of $61.5 billion.

Congress must adopt a final 1978 spending and taxing agenda by Sept. 15. While the President still proposes a budget, with spending initiatives that are important prods to Congress, the House and the Senate now set the final, binding spending plans for the nation under a procedure put into effect with the current fiscal year.

Congress makes most of the difficult budget decisions in the spring when the House and Senate agree on a tentative spending and taxing plan.

The decisions the committees faced in the so-called second concurrent resolution dealt with big increases in farm supports, financing Social Security and the President's energy program.

The Senate voted to set farm spending at $5.6 billion, $1.25 billion more than the level Congress set last spring, but $500 million less than the House Budget Committee voted last week.

The Senate committee yesterday defeated an attempt by Sen. J. Bennett Johnson (D-La.) to add another $200 million to finance a sugar price support program proposed by the administration.

The Senate passed a farm bill last May setting a spending level of $5.6 billion. The House bill, passed last week, adds another $200 million for sugar and boosts corn price supports by $400 million over the Senate bill.

The House and Senate were in conference late last night trying to resolve the differences between the two bills.

The budget proposed yesterday by the committee orders the Senate to reduce farm spending to $5.6 billion if it should pass a farm bill bigger than the one envisioned in the budget.

The Carter administration had indicated that it would veto farm spending in excess of the $4.1 billion level it recommended, but congressional sources say the President has backed off the veto threat.

Both Sen. Edmund S. Muskie (D-Maine) and Rep. Robert N. Giaimo (D-Conn.), chairmen of the budget committees, have criticized Congress and the President for allowing crop support payments to rise out of proportion. Giaimo, however, resisted putting a directive in the House committee's budget that would force a retroactive decrease in farm spending.

The committee yesterday also decided that the President's proposal to transfer $5.2 billion in general funds to the Social Security trust funds would not take place in fiscal 1978, and it made no changes in Social Security funding for 1978.

The committee also voted to trim back sharply a $5 billion program approved by the House Budget Committee last week to provide special financing for home owners to insulate their dwellings. The Senate voted $2 billion in spending authority for the program, which would be run through the Government National Mortgage Association.

The deficit levels approved by the House and Senate committees, as well as the one advocated by President Carter, are mush larger than the $45 billion or so the government is expected to be in the red this year.

The Democratic majority in the House and Senate, as well as administration officials, say that a bigger deficit is needed next year - even though it is a year further to the administration's goal of balancing the budget by 1981 - because bigger public employment and public works programs are needed for continued recovery.